[clang-tools-extra] Refactor clang doc comment structure (PR #142273)

[Samarth Narang via cfe-commits]

snarang181 wrote:

Left a reply to this [comment](https://github.com/llvm/llvm-project/pull/142273/files#r2125020120) @ilovepi. Addressed some other comments. 

https://github.com/llvm/llvm-project/pull/142273