Fixes Alt + click behaviour when rows are wrapped

[kumaran-14]

Fixes #2658.

[kumaran-14]

@Tyriar Some MoveToCell tests are failing. Should they be updated or, my implementation is wrong?

[Tyriar]

@kumaran-14 well this test was enforcing the old behavior which you've now broken:

 MoveToCell
       normal buffer
         should ignore the Y value

You'll need to update the test to respect the new behavior. Make sure there's a test for moving across a single line and multiple lines as well.

[kumaran-14]

@Tyriar can you look into this?

[Tyriar]

@kumaran-14 I'll probably free up next week to power through xterm.js stuff and release 4.4

[kumaran-14]

@Tyriar Sure. That sounds awesome. I'd like to finish this and contribute more.

[Tyriar]

It only seems to wrap around 1 row currently, so if the prompt spans multiple rows you need multiple clicks to get it where you want it.

[Tyriar]

Another thing I noticed is that the current algorithm doesn't look at whether the row is wrapped, it should only move along the current wrapped row. I'm looking into fixing these issues now so we can get this merged in.

[kumaran-14]

@Tyriar How do I get the positions of buffer end?

[kumaran-14]

CI fails on windows and mac, passes on Linux.
What system did you test on?
I get this behaviour on Linux

[Tyriar]

Thanks for the PR @kumaran-14, I made a couple of changes including adding some more complete tests so we can merge this in.

[kumaran-14]

@Tyriar Sure. Glad to help.