[3.8] bpo-36390: Gather IDLE Format menu functions into format.py (GH-14827) by miss-islington · Pull Request #14829 · python/cpython

@terryjreedy @miss-islington

…-14827)

Add two indent spec methods from editor and Rstrip to existing file.
Tests are not added for indent methods because they need change
in lights of 3.x's prohibition on mixing tabs and spaces.
(cherry picked from commit 1b38922)

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>