[clang] [Clang SA]: add support for mismatched ownership_returns+ownership_takes calls for custom allocation classes (PR #98941)

[Balazs Benics via cfe-commits]

https://github.com/steakhal commented:

It looks great! I only had one more thing to test.
Besides that it would be nice to advertise this in the `clang/docs/ReleaseNotes.rst`.
Usually, from that release notes we also link to the checker or the relevant doc pages - in this case it would be nice to link to the docs of this attribute - which does not really elaborate on the attribute and the semantics.

Do you want to extend the scope of this PR to add some minimal docs to the attribute?
If not, that's also fine, we will create a separate ticket for adding them later.

https://github.com/llvm/llvm-project/pull/98941