* We split stepping for source debugging into step over/into/out depending on
how it handles function calls. Step Into is the same behaviour as before - it
steps to the next source line executed regardless of if it's inside a function
call. Step Over is similar but will not enter function calls. We define that
as the callstack growing (so staying the same or shrinking - returning from a
function - is OK), and this is as accurate as the underlying debug
information. Step Out will run until the callstack shrinks, i.e. returning
from a function.
* This is a slight behaviour change of keyboard shortcuts - F10 was effectively
doing step into and will now step over. F11 will step into which is the old
behaviour.
* All these variants have backwards versions, and to remain consistent we keep
the shift modifier as forwards/backwards. This differs from visal studio where
step out is shift-F10.
* The seems like the best balance - using any other variant would likely confuse
muscle memory of anyone used to visual studio (where these shortcuts are
intended to mimick), if only because F10 would be step into whether or not F11
is used for step over or some other key which would likely be even more
confusing either way. Trying to twist to use Shift-F10 for step out would be
inconsistent with the other backwards running operations and likely cause more
confusion than it saves in matching VS's shortcuts exactly. Also an accidental
Shift-F10 is not too destructive, the user can realise it didn't Step Out
forwards, and press Ctrl-F10 or look up the button.
* The hope is that most likely people doing source debugging and familiar with
these keys expect F10 to step over, so the previous behaviour was unexpected
but easy to work around, and that changing the meaning of the key won't
disrupt them. Or at least the disruption is less than other alternatives.