Modernize python type hints for apache_beam.

[robertwb]

This was done with com2ann plus some manaual edits.

---

Thank you for your contribution! Follow this checklist to help us incorporate your contribution quickly and easily:

• Mention the appropriate issue in your description (for example: addresses #123), if applicable. This will automatically add a link to the pull request in the issue. If you would like the issue to automatically close on merging the pull request, comment fixes #<ISSUE NUMBER> instead.
• Update CHANGES.md with noteworthy changes.
• If this contribution is large, please file an Apache Individual Contributor License Agreement.

See the Contributor Guide for more tips on how to make review process smoother.

To check the build health, please visit https://github.com/apache/beam/blob/master/.test-infra/BUILD_STATUS.md

GitHub Actions Tests Status (on master branch)

See CI.md for more information about GitHub Actions CI or the workflows README to see a list of phrases to trigger workflows.

[robertwb]

R: @tvalentyn

[github-actions]

Stopping reviewer notifications for this pull request: review requested by someone other than the bot, ceding control. If you'd like to restart, comment assign set of reviewers

[tvalentyn]

cc: @jrmccluskey

[tvalentyn]

Reopening to rerun the test in case master changed

[robertwb]

Thanks. I thought all tests were passing before, I'll look into the failure here. (I do see a lot of

>   self._maybe_sample_exception(exc_info, windowed_value)
E   TypeError: Argument 'exn' has incorrect type (expected BaseException, got tuple)

which is a bit odd.)

[jrmccluskey]

Thanks. I thought all tests were passing before, I'll look into the failure here. (I do see a lot of

>   self._maybe_sample_exception(exc_info, windowed_value)
E   TypeError: Argument 'exn' has incorrect type (expected BaseException, got tuple)

which is a bit odd.)

those should be fixed now, @damccorm addressed those this week

[damccorm]

Yeah, you may need to push a dummy commit to rerun though

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 58.99%. Comparing base (f4d07c4) to head (2d69dde).
Report is 41 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #32872      +/-   ##
============================================
+ Coverage     58.87%   58.99%   +0.12%     
  Complexity     3112     3112              
============================================
  Files          1130     1133       +3     
  Lines        174455   174905     +450     
  Branches       3343     3343              
============================================
+ Hits         102716   103193     +477     
+ Misses        68392    68365      -27     
  Partials       3347     3347              

Flag	Coverage Δ
python	81.58% <100.00%> (+0.15%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

---

🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests
• JS Bundle Analysis - Avoid shipping oversized bundles