Sphinx-autodoc-typehints

- Fix `fully_qualified` should be `typehints_fully_qualified`

- Resolve type guard imports before evaluating annotations for objects
- Remove `set_type_checking_flag` flag as this is now done by default
- Fix crash when the `inspect` module returns an invalid python syntax source
- Made formatting function configurable using the option `typehints_formatter`

- Fixed `normalize_source_lines()` messing with the indentation of methods with decorators that have parameters starting
with `def`.
- Handle `ValueError` or `TypeError` being raised when signature of an object cannot be determined
- Fix `KeyError` being thrown when argument is not documented (e.g. `cls` argument for class methods, and `self` for
methods)

- Added `typehints_defaults` config option allowing to automatically annotate parameter defaults.

- Fixed `NewType` inserts a reference as first argument instead of a string

- Dropped Python 3.6 support
- Python 3.10 support
- Normalize async functions properly
- Allow py310 style annotations (PEP-563)