Add typing for _wait_for_object.py

[CoolCat467]

This PR adds type annotations to _wait_for_object.py and _core/_windows_cffi.py

I would love feedback and any comments on how this could be improved to be more accurate.

[codecov]

Codecov Report

Merging #2755 (dc0b608) into master (9028678) will increase coverage by 0.00%.
The diff coverage is 100.00%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2755   +/-   ##
=======================================
  Coverage   98.94%   98.94%           
=======================================
  Files         113      113           
  Lines       16794    16837   +43     
  Branches     3030     3036    +6     
=======================================
+ Hits        16616    16659   +43     
  Misses        123      123           
  Partials       55       55           

Files Changed	Coverage Δ
trio/_core/_tests/test_windows.py	100.00% <100.00%> (ø)
trio/_core/_windows_cffi.py	100.00% <100.00%> (ø)
trio/_wait_for_object.py	100.00% <100.00%> (ø)

[TeamSpen210]

I think you might need to access it via cffi.FFI.CData, on the class.

[CoolCat467]

If anyone has any ideas, the only issue the CI has is the mypy run for windows, saying

trio/_core/_windows_cffi.py:225: error: Name "ffi.CData" is not defined  [name-defined]

[jakkdl]

pyproject.toml