[clang-tools-extra] [clang-doc] fix CSS, JS paths for HTML Mustache generation (PR #160360)

[Erick Velez via cfe-commits]

evelez7 wrote:

### Merge activity

* **Sep 24, 12:54 AM UTC**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/160360).


https://github.com/llvm/llvm-project/pull/160360