[clang] Retrieve BinaryOperator::getOpcode and BinaryOperator::getOpcodeStr via libclang and its python interface (PR #98489)

[Jannick Kremer via cfe-commits]

DeinAlptraum wrote:

For a quick overview of the changes you'll need to make after #95608  in the Python bindings:
- remove `_kind`, `_name_map` and `__repr__()` from the `BinaryOperator` definition
- declare all variants of `BinaryOperator` within the class definition, i.e. `Invalid = 0` instead of `BinaryOperator.Invalid = BinaryOperator(0)`
- add `BinaryOperator` to the list of enum kinds tested in `clang/bindings/python/tests/cindex/test_enums.py`

https://github.com/llvm/llvm-project/pull/98489