Fix macros in changelog (elastic#30269)

remove comments for macros which caused macros not to work correctly

Author: Paul Sanwald

docs/CHANGELOG.asciidoc

@@ -1,7 +1,7 @@
 // Use these for links to issue and pulls. Note issues and pulls redirect one to
 // each other on Github, so don't worry too much on using the right prefix.
-// :issue: https://github.com/elastic/elasticsearch/issues/
-// :pull: https://github.com/elastic/elasticsearch/pull/
+:issue: https://github.com/elastic/elasticsearch/issues/
+:pull: https://github.com/elastic/elasticsearch/pull/
 
 = Elasticsearch Release Notes