fix: dislocation of cursor after previous_history navigation to a multiline entry

[blindFS]

Fixes this bug:

When I press ctrl-p/up to bring up this kind of command:

The cursor is at the end of the first line. However when I press left/right key to move the cursor, it unexpectedly jumps to the last line and executes the movement there.

After pressing left:

After this PR, however.

It shows the cursor directly at the end of the last line, just like selecting that entry in a history menu will do.

The same thing happens for vi normal mode.

[fdncred]

This has annoyed me for years. Glad you fixed it.

[Bahex]

Is there a reason we didn't move ahead with this?

[fdncred]

other reviews. if you think it's good, let's land it.