static/frontend: add noindex tag to metadata pages

There is not much utility in indexing metadata pages so we will
tell search engines to skip them during indexing.

Change-Id: I7b1bf7f5a29d6f7eb1b5d882b734e74aa0e80b9d
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/341865
Trust: Jamal Carvalho <jamal@golang.org>
Reviewed-by: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Julie Qiu <julie@golang.org>
Run-TryBot: Jamal Carvalho <jamal@golang.org>
TryBot-Result: kokoro <noreply+kokoro@google.com>
diff --git a/static/frontend/frontend.tmpl b/static/frontend/frontend.tmpl
index 4fcf25e..e07d196 100644
--- a/static/frontend/frontend.tmpl
+++ b/static/frontend/frontend.tmpl
@@ -25,6 +25,7 @@
     {{block "description" .}}
       <meta name="description" content="Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.">
     {{end}}
+    {{block "robots" .}}{{end}}
     <meta class="js-gtmID" data-gtmid="{{.GoogleTagManagerID}}">
     <link rel="shortcut icon" href="/static/shared/icon/favicon.ico">
     {{block "canonical" .}}{{end}}
diff --git a/static/frontend/unit/importedby/importedby.tmpl b/static/frontend/unit/importedby/importedby.tmpl
index 08e714e..2066868 100644
--- a/static/frontend/unit/importedby/importedby.tmpl
+++ b/static/frontend/unit/importedby/importedby.tmpl
@@ -4,6 +4,10 @@
   license that can be found in the LICENSE file.
 -->
 
+{{define "robots"}}
+  <meta name="robots" content="noindex">
+{{end}}
+
 {{define "main-styles"}}
   <link href="/static/frontend/unit/importedby/importedby.css?version={{.AppVersionLabel}}" rel="stylesheet">
 {{end}}
diff --git a/static/frontend/unit/imports/imports.tmpl b/static/frontend/unit/imports/imports.tmpl
index 65451c8..265d7ce 100644
--- a/static/frontend/unit/imports/imports.tmpl
+++ b/static/frontend/unit/imports/imports.tmpl
@@ -4,6 +4,9 @@
   license that can be found in the LICENSE file.
 -->
 
+{{define "robots"}}
+  <meta name="robots" content="noindex">
+{{end}}
 
 {{define "main-styles"}}
   <link href="/static/frontend/unit/imports/imports.css?version={{.AppVersionLabel}}" rel="stylesheet">
diff --git a/static/frontend/unit/licenses/licenses.tmpl b/static/frontend/unit/licenses/licenses.tmpl
index beb6c6b..70c9ae4 100644
--- a/static/frontend/unit/licenses/licenses.tmpl
+++ b/static/frontend/unit/licenses/licenses.tmpl
@@ -4,6 +4,10 @@
   license that can be found in the LICENSE file.
 -->
 
+{{define "robots"}}
+  <meta name="robots" content="noindex">
+{{end}}
+
 {{define "main-styles"}}
   <link href="/static/frontend/unit/licenses/licenses.css?version={{.AppVersionLabel}}" rel="stylesheet">
 {{end}}
diff --git a/static/frontend/unit/versions/versions.tmpl b/static/frontend/unit/versions/versions.tmpl
index 48dc929..02b28c9 100644
--- a/static/frontend/unit/versions/versions.tmpl
+++ b/static/frontend/unit/versions/versions.tmpl
@@ -4,6 +4,10 @@
   license that can be found in the LICENSE file.
 -->
 
+{{define "robots"}}
+  <meta name="robots" content="noindex">
+{{end}}
+
 {{define "main-styles"}}
   <link href="/static/frontend/unit/versions/versions.css?version={{.AppVersionLabel}}" rel="stylesheet">
 {{end}}