design/14951: fix wrong issue link

Change-Id: I054a71b08fabb60db7d334735ceabeb6bde3f604
Reviewed-on: https://go-review.googlesource.com/123195
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/design/14951-soft-heap-limit.md b/design/14951-soft-heap-limit.md
index a3f82f8..bac5f9b 100644
--- a/design/14951-soft-heap-limit.md
+++ b/design/14951-soft-heap-limit.md
@@ -6,7 +6,7 @@
 
 Last updated: 2017-10-31
 
-Discussion at https://golang.org/issue/13951.
+Discussion at https://golang.org/issue/14951.
 
 ## Background