Fixes:
* Types in binary unions as per [PEP
604](https://peps.python.org/pep-0604/) not highlighted;
* `except*` keyword not highlighted;
* Classes beginning with `_` not recognized as such, however `_` is a
valid first character for private classes; additionally the regex for
parsing constant/class names appeared inconsistent and incomplete so was
adjusted;
* Builtin types such as `float`, `dict`, etc not recognized as types;
* **Update:** decorators with arguments not recognized as decorators;
* **Update:** docstrings after type alias assignments not recognized as
docstrings;
* **Update:** `and/in/is/not/or/is not/not in` not capturable as
keywords;
* **Update:** decorators with "nesting" (@x.y.z) not recognized as
decorators;
Before:

After:

Release Notes:
- N/A
---------
Co-authored-by: Piotr Osiewicz <24362066+osiewicz@users.noreply.github.com>