[clang] Add ElaboratedType sugaring for types on implicit special members

Extend the change from commit 15f3cd6b ([clang] Implement
ElaboratedType sugaring for types written bare, 2021-10-11, D112374)
to cover types in the signatures of implicit copy-constructor,
copy-assignment, move-constructor, and move-assignment members in
C++ record types.

With this fix, diagnostic messages print types of special members
consistently whether they are explicitly or implicitly defined.

Fixes: https://github.com/llvm/llvm-project/issues/59557

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D141441