Add CI report of typehint completeness

[cspotcode]

Pyright has a flag to check how much of a library's API is properly typehinted. This PR generates that report on CI.

Output looks like this:
https://github.com/pythonarcade/arcade/actions/runs/5137377588/jobs/9245379193?pr=1807

It generates a summary at the bottom:

Symbols exported by "arcade": 9419
  With known type: 3363
  With ambiguous type: 442
  With unknown type: 5614
  Functions without docstring: 768
  Functions without default param: 38
  Classes without docstring: 150

Other symbols referenced but not exported by "arcade": 1151
  With known type: 877
  With ambiguous type: 54
  With unknown type: 220

Type completeness score: 35.7%

It would be great to see how much @gran4's PRs improve this score.