Cleanup type hints + spelling, source API links

[ryancoe]

Description

As I am using the fancy new VS Code IDE, I was made aware of a couple minor mistakes in our type hints and spelling typos.

• Type Hints errors
• Type Hints using Optional type (https://docs.python.org/3/library/typing.html#typing.Optional)
• Spelling
• Source API links in docs (https://www.sphinx-doc.org/en/master/usage/restructuredtext/domains.html#cross-referencing-python-objects)

Checklist for PR

• Authors read the contribution guidelines
• The pull request is from an issue branch (not main) on your fork to the main branch in WecOptTool.
• The authors have given the admins edit access
• All changes adhere to the style guide including PEP8, Docstrings, and Type Hints.
  Added note in Changelog
  Modified the documentation if applicable
  Modified or added a new test
• All tests pass
• Documentation builds
  Reference or close any relevant issues

[cmichelenstrofer]

That was a lot of typos! Maybe I don't have spell check on in VS Code.

[ryancoe]

I'm going to hold off until #53 is merged and then update type | None to Optional[type]