Fix zz updating desired column

[schu34]

What this PR does / why we need it:
basically the same as #4298. That PR was causing a bunch of difficult to debug issues since it updated the default behaviour for all actions. This PR takes mostly the same approach, except it defaults doesntChangeDesiredColumn to false and just sets it to true for zz. There are probably other actions that update desiredColumn when they shouldn't, and this PR won't address those, but at least now there's an easy route to address those bugs as they're noticed. (just add doesntChangeDesiredColumn = true)

I also added a bunch of unit tests that I wrote while trying to debug the last PR.

Which issue(s) this PR fixes
#4296

Special notes for your reviewer:

[J-Fields]

Thanks @schu34, going with this less disruptive approach is probably better, even if there's some subtle existing misbehavior we haven't caught.

[J-Fields]

What about other commands which move the view, but (generally) not the cursor? For instance, zt/zb or <C-e>/`?

[schu34]

Yeah sure, wasn't aware of all those but easy enough to add. Is there a list of commands that move the view but not the cursor that I could reference?

[J-Fields]

Not that I know of. Maybe H/L/M too? I can't right now but before I merge I'll double check that these all do behave this way in vim and we didn't miss anything too obvious.

[schu34]

did some testing in neovim. It seems that all the z commands as well as <C-e> don't update the desiredColumn but H/L/M/<C-y> take you to the first non-whitespace character of the line so they do.

[J-Fields]

I think that behavior is dependent on startofline being set. Can you double check that the desired column isn't updated when that's unset?

[schu34]

Yeah, you're right about startofline, in actual vim when it's not set the desired column isn't updated. but it seems like the plugin currently doesn't respect startofline for H/L/M anyway unless I'm missing something. In any case, should I update doesntChangeDesiredColumn to be a function so it can change values based on config options?

[J-Fields]

Thanks for pointing that out, I just created #4428.

Yeah, if you could make doesntChangeDesiredColumn a function in preparation for that change, that'd be awesome

[schu34]

Alright updated that and also removed it from BaseMovement since that inherits from BaseAction

[J-Fields]

I think you missed <C-y>. Other than that, looks good to me. Thanks a lot for the rapid iteration on this!

[J-Fields]

Thanks again! I'll merge once the tests are confirmed to be green