Rendering glitches when terminal height changed

[rgwood]

I've noticed a rendering glitch in the demo example (cargo run --example demo) when the terminal is resized. Detailed reproduction:

1. Press ctrl+l to clear the screen:

2. Press enter:

3. Make the window 1 row taller (dragging from the bottom):

Note that our text has all moved up by 1 row, which doesn't seem right.

4. Press a:

Note that the cursor is not on the same line as a.

5. Press b:

The line with ab looks good but the row with only a shouldn't be there.

Version info

Terminal: Windows Terminal Preview v1.16.3464.0
OS: Linux (in WSL2)
Reedline 3d83306