[clang-tools-extra] [clang-doc] Add start and end line numbers (PR #137732)

[Paul Kirth via cfe-commits]

ilovepi wrote:

hmm. Premege checks are broken due to #137876. Given that they  passed before, still pass locally, and I only removed some extraneous code I'm landing this w/o them passing.

https://github.com/llvm/llvm-project/pull/137732