Also add .pyi to the python extensions in the "File-open" and "File-save" dialogues.
Add util.py to contain objects that are used in multiple idlelib modules
and have no dependencies on any of them.
Co-authored-by: E-Paine <63801254+E-Paine@users.noreply.github.com>
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
(cherry picked from commit 50cf4991c4)
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Terry Jan Reedy