Pass mypy and link issues

[Avasam]

Ref: https://github.com/jaraco/skeleton/issues/143

Upstream issues:

• https://github.com/jaraco/jaraco.windows/issues/27
• https://github.com/jaraco/jaraco.ui/issues/4
• https://github.com/jaraco/jaraco.text/issues/17
• https://github.com/jaraco/jaraco.structures/issues/2
• https://github.com/python/typeshed/issues/12595

This does changes some imports with the assumption that older Python versions are no longer supported.