Enable adding/removing a breakpoint via mouse clicks in the changes/diff editor on a changed line

[sean-mcmanus]

Enable adding/removing breakpoints via mouse clicks in the changes/dif editor on a changed line. Maybe it could show a popup for the 2 different options (toggle breakpoint and the -> icon, whatever that is called).

Right now, the breakpoint can't be added/removed because the -> icon blocks it. See the screenshot. The workaround is to use a keyboard shortcut.

[roblourens]

A worse example of this, the decoration for the current line with a breakpoint + the test checkmark: #166267 (comment)

[roblourens]

I just saw this older issue, if you haven't seen it @hediet #114776. Maybe this is a dupe.

[hediet]

/duplicate #114776