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/gpui/src/platform/linux/platform.rs

@@ -507,6 +507,8 @@ impl CursorStyle {
             CursorStyle::ResizeUp => Shape::NResize,
             CursorStyle::ResizeDown => Shape::SResize,
             CursorStyle::ResizeUpDown => Shape::NsResize,
+            CursorStyle::ResizeColumn => Shape::ColResize,
+            CursorStyle::ResizeRow => Shape::RowResize,
             CursorStyle::DisappearingItem => Shape::Grabbing, // todo(linux) - couldn't find equivalent icon in linux
             CursorStyle::IBeamCursorForVerticalLayout => Shape::VerticalText,
             CursorStyle::OperationNotAllowed => Shape::NotAllowed,
@@ -533,6 +535,8 @@ impl CursorStyle {
             CursorStyle::ResizeUp => "n-resize",
             CursorStyle::ResizeDown => "s-resize",
             CursorStyle::ResizeUpDown => "ns-resize",
+            CursorStyle::ResizeColumn => "col-resize",
+            CursorStyle::ResizeRow => "row-resize",
             CursorStyle::DisappearingItem => "grabbing", // todo(linux) - couldn't find equivalent icon in linux
             CursorStyle::IBeamCursorForVerticalLayout => "vertical-text",
             CursorStyle::OperationNotAllowed => "not-allowed",