mod.md: correct some links

Change-Id: Ib0c4611c84c7eca652c6128faa8645be7c9ec9f0
Reviewed-on: https://go-review.googlesource.com/c/website/+/362034
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Carlos Amedee <carlos@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
diff --git a/_content/ref/mod.md b/_content/ref/mod.md
index 4fd2f38..dd4ebc5 100644
--- a/_content/ref/mod.md
+++ b/_content/ref/mod.md
@@ -540,7 +540,7 @@
 
 The `go` directive was originally intended to support backward incompatible
 changes to the Go language (see [Go 2
-transition](/design/28221-go2-transitions)). There have been no incompatible
+transition](https://go.googlesource.com/proposal/+/master/design/28221-go2-transitions.md)). There have been no incompatible
 language changes since modules were introduced, but the `go` directive still
 affects use of new language features:
 
@@ -1052,7 +1052,7 @@
 default version (for example, to prune the `go.sum` file more aggressively in a
 `go 1.17` module).
 
-See [the design document](/design/36460-lazy-module-loading) for more detail.
+See [the design document](https://go.googlesource.com/proposal/+/master/design/36460-lazy-module-loading.md) for more detail.
 
 ### Lazy module loading {#lazy-loading}