[clang-tools-extra] [clang-doc] remove indentation for preformatted text (PR #166672)

[Erick Velez via cfe-commits]

evelez7 wrote:

### Merge activity

* **Nov 7, 9:10 PM UTC**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.com/github/pr/llvm/llvm-project/166672).


https://github.com/llvm/llvm-project/pull/166672