wayland: Implement cursor-shape-v1 (#11106)

Fixes wrong cursor icons and sizes on KDE 6 (and possibly other
compositors)

Gnome still doesn't support this protocol, so to fix cursor settings
there we'll need to read `gsettings`.

Before:

![image](https://github.com/zed-industries/zed/assets/71973804/f0c3dc1b-2bed-43f7-b579-df6c9c0b547f)

After:

![image](https://github.com/zed-industries/zed/assets/71973804/6de639f9-653d-4896-80ca-b7c69641eded)


Release Notes:

- N/A

crates/gpui/src/platform.rs

@@ -715,7 +715,7 @@ pub enum PromptLevel {
 }
 
 /// The style of the cursor (pointer)
-#[derive(Copy, Clone, Debug)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
 pub enum CursorStyle {
     /// The default cursor
     Arrow,