doc/go1.19: move the description of the runtime.GOROOT change from 'cmd/go' to 'runtime'

Even though the change in the behavior of 'runtime.GOROOT' was
not actually due to a change in the runtime package proper, I
suspect that users who notice it will look for the release note
in that section, not the 'cmd/go' section.

Fixes #51461.

Change-Id: I271752968d4152a7fdf3e170537e3072bf87ce86
Reviewed-on: https://go-review.googlesource.com/c/go/+/400814
Reviewed-by: Ian Lance Taylor <[email protected]>

Author: Bryan C. Mills

doc/go1.19.html

@@ -36,11 +36,6 @@ <h3 id="go-command">Go command</h3>
 </p>
 
 <!-- https://go.dev/issue/51461 -->
-<p>
-  Passing the <code>-trimpath</code> flag to <code>go</code> commands now
-  causes <code>runtime.GOROOT()</code> in the resulting binary to return the
-  empty string instead of the string <code>"go"</code>.
-</p>
 <p>
   The <code>-trimpath</code> flag, if set, is now included in the build settings
   stamped into Go binaries by <code>go</code> <code>build</code>, and can be
@@ -137,6 +132,17 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
   </dd>
 </dl><!-- net -->
 
+<dl id="runtime"><dt><a href="/pkg/runtime/">runtime</a></dt>
+  <dd>
+    <p><!-- https://go.dev/issue/51461 -->
+      The <code>GOROOT</code> function now returns the empty string
+      (instead of <code>"go"</code>) when the binary was built with
+      the <code>-trimpath</code> flag set and the <code>GOROOT</code>
+      variable is not set in the process environment.
+    </p>
+  </dd>
+</dl><!-- runtime -->
+
 <dl id="strconv"><dt><a href="/pkg/strconv/">strconv</a></dt>
   <dd>
     <p><!-- CL 397255 -->