Convert mouse y to line number in the sidebar rather than the text.
(cherry picked from commit 86f1a18abf)
Co-authored-by: Tal Einat <taleinat+github@gmail.com>
They pass with tk 8.5.9 (Azure) but fail with the 8.6.x we install.
(cherry picked from commit e8874b85b4)
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>