bpo-32989: IDLE - fix bad editor call of pyparse method (GH-5968)


Fix comments and add tests for editor newline_and_indent_event method.
Remove unused None default for function parameter of pyparse find_good_parse_start method
and code triggered by that default.

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
(cherry picked from commit ec64640a2c5236d7a5d5470d759172a3d93eab0b)

Co-authored-by: Cheryl Sabella <cheryl.sabella@gmail.com>
6 files changed