Add missing GitHub issue link to 0.15.1 release notes

Author: LiamSwayne

src/download/0.15.1/release-notes.html

@@ -2173,7 +2173,7 @@ <h1>0.15.1 Release Notes</h1>
 
     {#header_open|zig objcopy regressed#}
     <p>Sorry, the code was not up to quality standards and must be reworked.
-    Some functionality remains; other functionality errors with "unimplemented". #24522</p>
+    Some functionality remains; other functionality errors with "unimplemented". <a href="https://github.com/ziglang/zig/issues/24522">#24522</a></p>
     {#header_close#}
     {#header_close#}