* Report bad-return-value-key for return values that cannot be accessed with Jinja's dot notation.
* Move constants into separate module.
* Add test to check FORBIDDEN_DICTIONARY_KEYS against current Python's key list.
* Remove unused constant.
* Apply suggestions from code review.
Co-authored-by: Matt Clay <matt@mystile.com>
* Add type annotations.
* Simplify typing.
Co-authored-by: Matt Clay <matt@mystile.com>
---------
Co-authored-by: Matt Clay <matt@mystile.com>