Add col/row resize cursor styles (#11406)

This PR fixes a small issue I noticed with resize cursors. The
column/row resize cursors were missing and in a few places we were using
`ew-resize` and `ns-resize` even though the documentation mentions
`col-resize` and `row-resize`.

Finally updated the panes in the workspace to use the new column/row
resize cursors.

Before:

![Screenshot_20240505_111515](https://github.com/zed-industries/zed/assets/829535/50f28a1b-33e2-431a-8fc8-5048d89c8f7b)

![Screenshot_20240505_111521](https://github.com/zed-industries/zed/assets/829535/45856f7e-4ca9-4b39-9f8c-144934e9d41e)

After:

![Screenshot_20240505_110606](https://github.com/zed-industries/zed/assets/829535/2b247ec1-44ef-4293-87b3-7fda4b2ebf8f)

![Screenshot_20240505_110611](https://github.com/zed-industries/zed/assets/829535/b558e1ce-3e08-4de3-8a11-6a80184d84fe)



Release Notes:

- Added column/row resize cursor styles to GPUI
- Fixed the existing references that were incorrectly using `ew-resize`
for column resize and `ns-resize` for row resize
- Updated panes to use column/row resize cursors instead on `ew-resize`
and `ns-resize`

---------

Co-authored-by: Mikayla <mikayla@zed.dev>

crates/workspace/src/pane_group.rs

@@ -914,8 +914,8 @@ mod element {
             for (ix, child) in &mut layout.children.iter_mut().enumerate() {
                 if let Some(handle) = child.handle.as_mut() {
                     let cursor_style = match self.axis {
-                        Axis::Vertical => CursorStyle::ResizeUpDown,
-                        Axis::Horizontal => CursorStyle::ResizeLeftRight,
+                        Axis::Vertical => CursorStyle::ResizeRow,
+                        Axis::Horizontal => CursorStyle::ResizeColumn,
                     };
                     cx.set_cursor_style(cursor_style, &handle.hitbox);
                     cx.paint_quad(gpui::fill(