[clang] [clang-tools-extra] [clang] Complete fields in __builtin_offsetof designators (PR #195126)

[Jakob Linke via cfe-commits]

schuay wrote:

Thanks for the review! Pushed a follow-up commit that filters bit-fields from the offsetof completion (since they are not valid as the second argument; `err_offsetof_bitfield`) and adds tests for both direct and indirect (anonymous-member) bit-fields.

https://github.com/llvm/llvm-project/pull/195126