blog: fix internal blog page links

When the blog moved from blog.golang.org/ to go.dev/blog/,
internal links like /blogpage needed to change to /blog/blogpage
and did not. This CL updates those links.

Fixes golang/go#47846.

Change-Id: I12a487062e19c7c5b619bd99f4488b3975e0d6d2
Reviewed-on: https://go-review.googlesource.com/c/website/+/344009
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Jamal Carvalho <jamal@golang.org>
diff --git a/go.dev/_content/blog/5years.md b/go.dev/_content/blog/5years.md
index 732553c..1c92449 100644
--- a/go.dev/_content/blog/5years.md
+++ b/go.dev/_content/blog/5years.md
@@ -24,7 +24,7 @@
 
 {{image "5years/gophers5th.jpg" 850}}
 
-[_Gopher_](/gopher) _illustration by_ [_Renee French_](http://reneefrench.blogspot.com.au/)
+[_Gopher_](/blog/gopher) _illustration by_ [_Renee French_](http://reneefrench.blogspot.com.au/)
 
 After the initial release, it took us a while to properly communicate the
 goals and design ethos behind Go. Rob Pike did so eloquently in his 2012 essay
diff --git a/go.dev/_content/blog/context.md b/go.dev/_content/blog/context.md
index be63d61..babeb33 100644
--- a/go.dev/_content/blog/context.md
+++ b/go.dev/_content/blog/context.md
@@ -44,7 +44,7 @@
 functions running on behalf of the `Context`: when the channel is closed, the
 functions should abandon their work and return.
 The `Err` method returns an error indicating why the `Context` was canceled.
-The [Pipelines and Cancelation](/pipelines) article discusses the `Done`
+The [Pipelines and Cancelation](/blog/pipelines) article discusses the `Done`
 channel idiom in more detail.
 
 A `Context` does _not_ have a `Cancel` method for the same reason the `Done`
diff --git a/go.dev/_content/blog/go1.12.md b/go.dev/_content/blog/go1.12.md
index 6bb8951..e68d6ff 100644
--- a/go.dev/_content/blog/go1.12.md
+++ b/go.dev/_content/blog/go1.12.md
@@ -12,7 +12,7 @@
 
 For details about the changes in Go 1.12, see the [**Go 1.12 release notes**](https://golang.org/doc/go1.12).
 
-Some of the highlights include [opt-in support for TLS 1.3](https://golang.org/doc/go1.12#tls_1_3), [improved modules support](https://golang.org/doc/go1.12#modules) (in preparation [for being the default in Go 1.13](/modules2019)), support for `windows/arm`, and [improved macOS & iOS forwards compatibility.](https://golang.org/doc/go1.12#darwin)
+Some of the highlights include [opt-in support for TLS 1.3](https://golang.org/doc/go1.12#tls_1_3), [improved modules support](https://golang.org/doc/go1.12#modules) (in preparation [for being the default in Go 1.13](/blog/modules2019)), support for `windows/arm`, and [improved macOS & iOS forwards compatibility.](https://golang.org/doc/go1.12#darwin)
 
 As always, we also want to thank everyone who contributed to this release by writing code, filing bugs, providing feedback, and/or testing the betas and release candidates.
 Your contributions and diligence helped to ensure that Go 1.12 is as stable as possible.
diff --git a/go.dev/_content/blog/migrating-to-go-modules.md b/go.dev/_content/blog/migrating-to-go-modules.md
index da586ba..8d5e43e 100644
--- a/go.dev/_content/blog/migrating-to-go-modules.md
+++ b/go.dev/_content/blog/migrating-to-go-modules.md
@@ -14,11 +14,11 @@
 
 This post is part 2 in a series.
 
-  - Part 1 — [Using Go Modules](/using-go-modules)
+  - Part 1 — [Using Go Modules](/blog/using-go-modules)
   - **Part 2 — Migrating To Go Modules** (this post)
-  - Part 3 — [Publishing Go Modules](/publishing-go-modules)
-  - Part 4 — [Go Modules: v2 and Beyond](/v2-go-modules)
-  - Part 5 — [Keeping Your Modules Compatible](/module-compatibility)
+  - Part 3 — [Publishing Go Modules](/blog/publishing-go-modules)
+  - Part 4 — [Go Modules: v2 and Beyond](/blog/v2-go-modules)
+  - Part 5 — [Keeping Your Modules Compatible](/blog/module-compatibility)
 
 **Note:** For documentation, see
 [Managing dependencies](https://golang.org/doc/modules/managing-dependencies)
@@ -280,7 +280,7 @@
 the `go.mod` file is backwards-compatible — but it's a significant change, and
 may expose existing problems. If you have existing version tags, you should
 increment the [minor version](https://semver.org/#spec-item-7). See
-[Publishing Go Modules](/publishing-go-modules) to learn how to increment and
+[Publishing Go Modules](/blog/publishing-go-modules) to learn how to increment and
 publish versions.
 
 ## Imports and canonical module paths
@@ -320,7 +320,7 @@
 Converting to Go modules should be a straightforward process for most users.
 Occasional issues may arise due to non-canonical import paths or breaking
 changes within a dependency.
-Future posts will explore [publishing new versions](/publishing-go-modules),
+Future posts will explore [publishing new versions](/blog/publishing-go-modules),
 v2 and beyond, and ways to debug strange situations.
 
 To provide feedback and help shape the future of dependency management in Go,
diff --git a/go.dev/_content/blog/module-compatibility.md b/go.dev/_content/blog/module-compatibility.md
index 4ace6a1..ff57b95 100644
--- a/go.dev/_content/blog/module-compatibility.md
+++ b/go.dev/_content/blog/module-compatibility.md
@@ -14,16 +14,16 @@
 
 This post is part 5 in a series.
 
-- Part 1 — [Using Go Modules](/using-go-modules)
-- Part 2 — [Migrating To Go Modules](/migrating-to-go-modules)
-- Part 3 — [Publishing Go Modules](/publishing-go-modules)
-- Part 4 — [Go Modules: v2 and Beyond](/v2-go-modules)
+- Part 1 — [Using Go Modules](/blog/using-go-modules)
+- Part 2 — [Migrating To Go Modules](/blog/migrating-to-go-modules)
+- Part 3 — [Publishing Go Modules](/blog/publishing-go-modules)
+- Part 4 — [Go Modules: v2 and Beyond](/blog/v2-go-modules)
 - **Part 5 — Keeping Your Modules Compatible** (this post)
 
 **Note:** For documentation on developing modules, see
 [Developing and publishing modules](https://golang.org/doc/modules/developing).
 
-Your modules will evolve over time as you add new features, change behaviors, and reconsider parts of the module's public surface. As discussed in [Go Modules: v2 and Beyond](/v2-go-modules), breaking changes to a v1+ module must happen as part of a major version bump (or by adopting a new module path).
+Your modules will evolve over time as you add new features, change behaviors, and reconsider parts of the module's public surface. As discussed in [Go Modules: v2 and Beyond](/blog/v2-go-modules), breaking changes to a v1+ module must happen as part of a major version bump (or by adopting a new module path).
 
 However, releasing a new major version is hard on your users. They have to find the new version, learn a new API, and change their code. And some users may never update, meaning you have to maintain two versions for your code forever. So it is usually better to change your existing package in a compatible way.
 
diff --git a/go.dev/_content/blog/publishing-go-modules.md b/go.dev/_content/blog/publishing-go-modules.md
index 7b95a8d..692787d 100644
--- a/go.dev/_content/blog/publishing-go-modules.md
+++ b/go.dev/_content/blog/publishing-go-modules.md
@@ -13,11 +13,11 @@
 
 This post is part 3 in a series.
 
-  - Part 1 — [Using Go Modules](/using-go-modules)
-  - Part 2 — [Migrating To Go Modules](/migrating-to-go-modules)
+  - Part 1 — [Using Go Modules](/blog/using-go-modules)
+  - Part 2 — [Migrating To Go Modules](/blog/migrating-to-go-modules)
   - **Part 3 — Publishing Go Modules** (this post)
-  - Part 4 — [Go Modules: v2 and Beyond](/v2-go-modules)
-  - Part 5 — [Keeping Your Modules Compatible](/module-compatibility)
+  - Part 4 — [Go Modules: v2 and Beyond](/blog/v2-go-modules)
+  - Part 5 — [Keeping Your Modules Compatible](/blog/module-compatibility)
 
 **Note:** For documentation on developing modules, see
 [Developing and publishing modules](https://golang.org/doc/modules/developing).
@@ -26,7 +26,7 @@
 on them.
 
 Please note: this post covers development up to and including `v1`. If you are
-interested in `v2`, please see [Go Modules: v2 and Beyond](/v2-go-modules).
+interested in `v2`, please see [Go Modules: v2 and Beyond](/blog/v2-go-modules).
 
 This post uses [Git](https://git-scm.com/) in examples.
 [Mercurial](https://www.mercurial-scm.org/),
diff --git a/go.dev/_content/blog/tidy-web.md b/go.dev/_content/blog/tidy-web.md
index cccc0dc..b469d86 100644
--- a/go.dev/_content/blog/tidy-web.md
+++ b/go.dev/_content/blog/tidy-web.md
@@ -6,7 +6,7 @@
 summary: Consolidating our web sites onto go.dev.
 ---
 
-In 2019, which seems like a decade ago, we [launched go.dev](/blog/go.dev),
+In 2019, which seems like a decade ago, we [launched go.dev](/blog/blog/go.dev),
 a new hub for Go developers, along with the [companion site pkg.go.dev](https://pkg.go.dev/),
 providing information about Go packages and modules.
 
diff --git a/go.dev/_content/blog/using-go-modules.md b/go.dev/_content/blog/using-go-modules.md
index e07a2c0..8d375b2 100644
--- a/go.dev/_content/blog/using-go-modules.md
+++ b/go.dev/_content/blog/using-go-modules.md
@@ -15,10 +15,10 @@
 This post is part 1 in a series.
 
   - **Part 1 — Using Go Modules** (this post)
-  - Part 2 — [Migrating To Go Modules](/migrating-to-go-modules)
-  - Part 3 — [Publishing Go Modules](/publishing-go-modules)
-  - Part 4 — [Go Modules: v2 and Beyond](/v2-go-modules)
-  - Part 5 — [Keeping Your Modules Compatible](/module-compatibility)
+  - Part 2 — [Migrating To Go Modules](/blog/migrating-to-go-modules)
+  - Part 3 — [Publishing Go Modules](/blog/publishing-go-modules)
+  - Part 4 — [Go Modules: v2 and Beyond](/blog/v2-go-modules)
+  - Part 5 — [Keeping Your Modules Compatible](/blog/module-compatibility)
 
 **Note:** For documentation on managing dependencies with modules, see
 [Managing dependencies](https://golang.org/doc/modules/managing-dependencies).
diff --git a/go.dev/_content/blog/v2-go-modules.md b/go.dev/_content/blog/v2-go-modules.md
index c8e040f..6acec11 100644
--- a/go.dev/_content/blog/v2-go-modules.md
+++ b/go.dev/_content/blog/v2-go-modules.md
@@ -14,11 +14,11 @@
 
 This post is part 4 in a series.
 
-  - Part 1 — [Using Go Modules](/using-go-modules)
-  - Part 2 — [Migrating To Go Modules](/migrating-to-go-modules)
-  - Part 3 — [Publishing Go Modules](/publishing-go-modules)
+  - Part 1 — [Using Go Modules](/blog/using-go-modules)
+  - Part 2 — [Migrating To Go Modules](/blog/migrating-to-go-modules)
+  - Part 3 — [Publishing Go Modules](/blog/publishing-go-modules)
   - **Part 4 — Go Modules: v2 and Beyond** (this post)
-  - Part 5 — [Keeping Your Modules Compatible](/module-compatibility)
+  - Part 5 — [Keeping Your Modules Compatible](/blog/module-compatibility)
 
 **Note:** For documentation on developing modules, see
 [Developing and publishing modules](https://golang.org/doc/modules/developing).