[tui][edi] Loss of caret focus bugs

[nazmulidris]

Cut line

Repro steps:

1. Open an existing MD file (which has more than 1 page in the viewport)
2. Scroll to some place on the 2nd page
3. Delete a line
4. The cursor is gone! You can still type stuff, just don't know where it's landing!

Delete last line

Repro steps:

1. Open an existing MD file (which has more than 1 page in the viewport)
2. Scroll to the last line
3. Delete it
4. The cursor is gone! You can still type stuff, just don't know where it's landing!

Wayland support?

Check for wayland support to still work. There were some issues in the rust-scratch/tty repo related to this.