[clang-tools-extra] [clang-doc] remove default label on some switches (PR #143919)

[Erick Velez via cfe-commits]

evelez7 wrote:

### Merge activity

* **Jun 13, 11:33 PM UTC**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/143919).


https://github.com/llvm/llvm-project/pull/143919