docs: Add new alias feature to release docs

docs/content/meta/release-notes.md

@@ -51,6 +51,7 @@ Hugo again continues its trend of each release being faster than the last. It's
   Possible values are `page`, `home`, `section`, `taxonomy`, and `taxonomyTerm`.
   (Internally, we also define `RSS`, `sitemap`, `robotsTXT`, and `404`, but those have no practical use for end users at the moment since they are not included in any collections.)
 * Add a `GitInfo` object to `Page` if `enableGitInfo` is set. It then also sets `Lastmod` for the given `Page` to the author date provided by Git. {{<gh 2291>}}
+* Implement support for alias templates  {{<gh 2533 >}}
 * New template functions:
   * Add `imageConfig` function {{<gh 2677>}}
   * Add `sha256` function {{<gh 2762>}}