[clang] [libclang/python] Add missing enum variants (PR #143264)

[Vlad Serebrennikov via cfe-commits]

Endilll wrote:

> Sidenote: I've noticed that a few enum variants have inconsistent namings, e.g. all Python enum variants are fully uppercase, execpt for StmtExpr. There's also CXCursor_CompoundAssignOperator which corresponds to COMPOUND_ASSIGNMENT_OPERATOR, i.e. slightly different names. I wonder if we should adapt these, but it might not be worth the breaking change.

Ideally I'd have enumerators with both correct and incorrect spelling, mark incorrect as deprecated, and phase it out, but `warning.deprecated()` is very helpfully a function decorator, so the typical way of doing that seems unavailable to us. Moreover, I see you judge completeness of enums by the number of enumerators, so we'll have to be careful about that, too.

https://github.com/llvm/llvm-project/pull/143264