[release-branch.go1.12] doc: correct link in 1.11.8 notes

Change-Id: I09e0c2720ec0a51dc73c24b4550a749448656025
Reviewed-on: https://go-review.googlesource.com/c/go/+/171143Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
(cherry picked from commit 6f512c8d)
Reviewed-on: https://go-review.googlesource.com/c/go/+/171157Reviewed-by: Andrew Bonventre <andybons@golang.org>

doc/devel/release.html

@@ -124,7 +124,7 @@ go1.11.7 (released 2019/04/05) includes fixes to the runtime and the
 <p>
 go1.11.8 (released 2019/04/08) fixes an issue where using the prebuilt binary
 releases on older versions of GNU/Linux
-<a href="https://golang/go/issues/31293">led to failures</a>
+<a href="https://golang.org/issues/31293">led to failures</a>
 when linking programs that used cgo.
 Only Linux users who hit this issue need to update.
 </p>