We're not fully standardising here: different contexts can store their range state however
they like. What we are standardising on is that now the view is always responsible for
highlighting the selected lines, meaning the context/controller needs to tell the view
where the range start is.
Two convenient benefits from this change:
1) we no longer need bespoke code in integration tests for asserting on selected lines because
we can just ask the view
2) line selection in staging/patch-building/merge-conflicts views now look the same as in
list views i.e. the highlight applies to the whole line (including trailing space)
I also noticed a bug with merge conflicts not rendering the selection on focus though I suspect
it wasn't a bug with any real consequences when the view wasn't displaying the selection.
I'm going to scrap the selectedRangeBgColor config and just let it use the single line
background color. Hopefully nobody cares, but there's really no need for an extra config.
Our refresh code may try to push a context. It does this in two places:
1) when all merge conflicts are resolved, we push a 'continue merge?' confirmation context
2) when all conflicts of a given file are resolved and we're in the merge conflicts context,
we push the files context.
Sometimes we push the confirmation context and then push the files context over it, so the user
never sees the confirmation context.
This commit fixes the race condition by adding a check to ensure that we're still in the
merge conflicts panel before we try escaping from it
This begins a big refactor of moving more code out of the Gui struct into contexts, controllers, and helpers. We also move some code into structs in the
gui package purely for the sake of better encapsulation
