vi mode cursor position isn't vi-like

[crides]

2 main issues I can observe:

1. Escape doesn't move the cursor back.

   For example, interleaving i and escape moves the cursor back one by one (in both vim and zsh vi mode)

2. Moving to the last character puts the cursor after the last character, not on top of it. Note: $ is not the only way to achieve this

   For example, having asdf and the cursor at the front (position 0), and pressing any one of w, W, E, e, $ in normal mode, or just pressing right arrows should put the cursor on top of f.

[jaredmontoya]

This needs to get fixed.
I think a lot of people who tried out nushell immediately went back to zsh after they found out how bad VI mode is.

[fdncred]

feel free to submit a fix for it. i'd like to see something like https://github.com/ulyssa/modalkit used to overhaul the vi mode.

[tanloong]

PR #699 is reverted in 6957b5a as it breaks the history traversal. Trying nushell for the first time and personally feeling very uncomfortable at current escaping behavior and hoping it can be fixed without any breaks.