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>

crates/vim/src/normal/increment.rs

@@ -26,13 +26,13 @@ impl_actions!(vim, [Increment, Decrement]);
 pub fn register(editor: &mut Editor, cx: &mut ViewContext<Vim>) {
     Vim::action(editor, cx, |vim, action: &Increment, cx| {
         vim.record_current_action(cx);
-        let count = vim.take_count(cx).unwrap_or(1);
+        let count = Vim::take_count(cx).unwrap_or(1);
         let step = if action.step { 1 } else { 0 };
         vim.increment(count as i64, step, cx)
     });
     Vim::action(editor, cx, |vim, action: &Decrement, cx| {
         vim.record_current_action(cx);
-        let count = vim.take_count(cx).unwrap_or(1);
+        let count = Vim::take_count(cx).unwrap_or(1);
         let step = if action.step { -1 } else { 0 };
         vim.increment(-(count as i64), step, cx)
     });