`Move(Big)WordRightEnd` is off-by-1 in insert mode

Platform Linux (NixOS)
Terminal software Wezterm

Using nushell 0.91.0

Steps to reproduce

1. In your nushell config, setup a keybind with:

    {
      name: move_to_end_word
      mode: [emacs vi_insert vi_normal]
      modifier: Alt keycode: Char_e
      event: {edit: MoveWordRightEnd}
    }
    {
      name: move_to_end_WORD
      mode: [emacs vi_insert vi_normal]
      modifier: Alt_Shift keycode: Char_E
      event: {edit: MoveBigWordRightEnd}
    }
   

2. Write this is some/cmd in nushell
3. Put cursor on s of some, make sure you are in insert mode:
   this is |some/cmd
4. Do Alt-e, cursor is now between m & e instead of between e & /:
   this is som|e/cmd
5. Do Alt-E, cursor is now between m & d instead of at the end of the input buffer:
   this is some/cm|d

Note that normal mode works okay, only insert mode isn't working correctly.

Screenshots/Screencaptures

https://github.com/nushell/reedline/assets/9730330/e722ee81-df56-4c77-9ca4-6a6fa898df8d

Reproduce the issue in nushell with the MoveWordRightEnd and MoveBigWordRightEnd keybindings, comparing vi insert mode with normal mode. Trace the implementations of these edit commands and their insert-mode handling; done means Alt-e stops after some and Alt-E reaches the end of some/cmd in insert mode while normal mode remains correct.