Add release verification step to release agent

Update release.agent.md to verify the new version appears
on the GitHub releases page after publishing.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: bschnurr

.github/agents/release.agent.md

@@ -131,15 +131,15 @@ When the pipeline completes signing, it will pause for manual validation before
 Once the pipeline has published successfully, verify the release:
 
 1. **Check GitHub Releases** — confirm the new version appears on the releases page:
-   `
+   ```
    gh release list --repo microsoft/vscode-python-debugger --limit 5
-   `
+   ```
    Or visit: https://github.com/microsoft/vscode-python-debugger/releases
 
 2. **Verify the release tag** matches the expected version (e.g. `v2026.4.0` — *example*):
-   `
+   ```
    gh release view v<VERSION> --repo microsoft/vscode-python-debugger
-   `
+   ```
 
 > ✋ **Confirm**: Does the new version appear on the [releases page](https://github.com/microsoft/vscode-python-debugger/releases)?