[clang-tools-extra] [clang-doc] add return comments to comment template (PR #150647)

[Erick Velez via cfe-commits]

evelez7 wrote:

### Merge activity

* **Jul 25, 6:41 PM UTC**: [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/150647) rebased this pull request as part of a merge.


https://github.com/llvm/llvm-project/pull/150647