Add support for resizing panes using vim motions (#21038)

Closes #8628

Release Notes:

- Added support for resizing the current pane using vim keybinds with
the intention to follow the functionality of vim
  - "ctrl-w +" to make a pane taller 
  - "ctrl-w -" to make the pane shorter
  - "ctrl-w >" to make a pane wider
  - "ctrl-w <" to make the pane narrower
- Changed vim pre_count and post_count to globals to allow for other
crates to use the vim count. In this case, it allows for resizing by
more than one unit. For example, "10 ctrl-w -" will decrease the height
of the pane 10 times more than "ctrl-w -"
- This pr does **not** add keybinds for making all panes in an axis
equal size and does **not** add support for resizing docks. This is
mentioned because these could be implied by the original issue

---------

Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>

assets/keymaps/vim.json

@@ -557,6 +557,10 @@
       "ctrl-w shift-l": ["workspace::SwapPaneInDirection", "Right"],
       "ctrl-w shift-k": ["workspace::SwapPaneInDirection", "Up"],
       "ctrl-w shift-j": ["workspace::SwapPaneInDirection", "Down"],
+      "ctrl-w >": ["vim::ResizePane", "Widen"],
+      "ctrl-w <": ["vim::ResizePane", "Narrow"],
+      "ctrl-w -": ["vim::ResizePane", "Shorten"],
+      "ctrl-w +": ["vim::ResizePane", "Lengthen"],
       "ctrl-w g t": "pane::ActivateNextItem",
       "ctrl-w ctrl-g t": "pane::ActivateNextItem",
       "ctrl-w g shift-t": "pane::ActivatePrevItem",