Remove deprecated windows note from WindowSizeMsg docstr

[Jaeiya]

I'm not sure if this is no longer an issue for all windows versions or just windows 10 & 11. I can only confirm 10 & 11. Let me know if there are any other considerations that need to be added or if we can just remove the note entirely, like I've done.

• I have read CONTRIBUTING.md.
• This pull request was approved to be created from a Discord conversation.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 55.64%. Comparing base (640d879) to head (4e8a048).
⚠️ Report is 5 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1695   +/-   ##
=======================================
  Coverage   55.64%   55.64%           
=======================================
  Files          25       25           
  Lines        1310     1310           
=======================================
  Hits          729      729           
  Misses        491      491           
  Partials       90       90           

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[meowgorithm]

We added the ability for Windows to detect terminal size changes a very long time ago, and it should work for both Windows 10 and 11. Thanks for this!