Improve changelog formatting

Co-authored-by: Michael B. Gale <mbg@github.com>

Author: henrymercer

CHANGELOG.md

@@ -4,7 +4,7 @@ See the [releases page](https://github.com/github/codeql-action/releases) for th
 
 ## [UNRELEASED]
 
-- The 'cleanup-level' input to the 'analyze' Action is now deprecated. The CodeQL Action has not written intermediate results to the database since version 2.2.5, so this option now has little to no practical use. [#2998](https://github.com/github/codeql-action/pull/2998)
+- The `cleanup-level` input to the `analyze` Action is now deprecated. The CodeQL Action has not written intermediate results to the database since version 2.2.5, so this option now has little to no practical use. [#2998](https://github.com/github/codeql-action/pull/2998)
 
 ## 3.29.5 - 29 Jul 2025