doc: add release note on dead global map variable deletion

Add a short release note blurb on linker dead-coding of global map
variables.

Updates #58645.

Change-Id: Ibfdd3e2b2b78517db4245b1d7eedd5e75a643b47
Reviewed-on: https://go-review.googlesource.com/c/go/+/498575
Reviewed-by: Eli Bendersky <eliben@google.com>
TryBot-Bypass: Than McIntosh <thanm@google.com>

diff --git a/doc/go1.21.html b/doc/go1.21.html
index 373be6c6868dcf28ed1594a96cb2e26ca45158cb..0bf89fe2128f4261d7806ddb28c50f65197c6b5d 100644 (file)
--- a/doc/go1.21.html
+++ b/doc/go1.21.html
@@ -190,9 +190,11 @@ Do not send CLs removing the interior tags from such phrases.
 </p>
 <!-- CL 463395 -->
 <p>
-  <!-- cmd/link: linker portion of dead map removal -->
+  In Go 1.21 the linker (with help from the compiler) is now capable of
+  deleting dead (unreferenced) global map variables, if the number of
+  entries in the variable initializer is sufficiently large, and if the
+  initializer expressions are side-effect free.
 </p>
-
 <p>
   TODO: complete this section, or delete if not needed
 </p>