pySCG: Python type hints and what they are for

[myteron]

Create a Python specific rule or recommendation around:

• Type hints and what they are for. Python 3.9 does not even throw an INFO or warn when type hints don't match, it has to be clear that type hints are not a security or robustness feature.
• Why type hints don't prevent implicit conversions
• Why hints must be used in combination with a tool like mypy
• Why or when mypy is unable to protect against issues on a deployed system.
  mypy != input sanitation or validation.
  Decide if its going to be a recommendation or rule after creating some content.

Avoid duplication with content in #712