Feature request: line numbers in Python Editor inputWidget

[mortimerb]

Summary

It would be very helpful to have line numbers in the Python Editor.

User story

What

Line numbers in the Python Editor inputWidget

Why

Errors in Python scripts run in the Python Editor are printed with their associated line number, but it's hard to find the exact line sometimes (especially in fairly long script) because there are no line numbers displayed in the inputWidget.

[johnhaddon]

Might be a good one for your list of quality-of-life improvements @ericmehl?