[clang] [ASTMatchers] AST matcher support for ObjC pointers (PR #117021)

[Rashmi Mudduluru via cfe-commits]

t-rasmud wrote:

> The changes LGTM as far as they go, but can you add details to the patch summary about why these should be exposed? (We typically only add to the AST matchers when there's an in-tree need for the functionality, so are there checks being updated to make use of these new interfaces or is this more of a change for completeness?)
> 
> Also, please add a release note to `clang/docs/ReleaseNotes.rst` so users know about the feature.

Thanks for the feedback @AaronBallman. I've updated the release notes and the PR summary.

https://github.com/llvm/llvm-project/pull/117021