[clang] [Sema] Add check for bitfield assignments to larger integral types (PR #68276)

[via cfe-commits]

vabridgers wrote:

I don't claim this is ready to merge, but I would like to get the review party started. I'm looking for constructive comments to advance this patch to a mergeable state. I don't do a lot of these patches, so have probably missed some basic things. Thanks.

https://github.com/llvm/llvm-project/pull/68276