[3.12] gh-120083: Add IDLE Hovertip foreground color needed for recent macOS (GH...

[3.12] gh-120083: Add IDLE Hovertip foreground color needed for recent macOS (GH-120605) (#122592)

On recent versions of macOS (sometime between Catalina and Sonoma 14.5), the default Hovertip foreground color changed from black to white, thereby matching the background. This might be a matter of matching the white foreground of the dark-mode text. The unreadable result is shown here (GH-120083 (comment)).

The foreground and background colors were made parameters so we can pass different colors for future additional hovertips in IDLE.

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(cherry picked from commit 5a7f7c48644baf82988f30bcb43e03dcfceb75dd)

Co-authored-by: John Riggles <jriggles@icloud.com>
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>