docs(marketing): update review command description to mention GitHub and GitLab PRs

For provenance purposes, this commit was AI assisted.

Author: backnotprop

apps/marketing/src/pages/index.astro

@@ -324,7 +324,7 @@ import AnnoReplace from '../components/landing/AnnoReplace.astro';
             </div>
             <div class="cap-item">
               <code class="cap-cmd">/plannotator-review</code>
-              <span class="cap-desc">Code review for uncommitted changes or a PR URL</span>
+              <span class="cap-desc">Code review for local changes or GitHub and GitLab PRs</span>
             </div>
           </div>
           <div class="cap-group">