[clang-tools-extra] reapply [clang-doc] Add --asset option to clang-doc (PR #96358)

[Paul Kirth via cfe-commits]

ilovepi wrote:

Can you update the commit message to describe why this can be relanded, and what this patch does? A good rule of thumb is to include the entire original commit message, followed by a short paragraph describing what's changed.

https://github.com/llvm/llvm-project/pull/96358