Make slash commands more discoverable (#12480)

<img width="648" alt="image"
src="https://github.com/zed-industries/zed/assets/482957/a63df904-fbbe-4e0a-80b2-c98ebee90690">

Release Notes:

- N/A

Co-authored-by: Nathan <nathan@zed.dev>

crates/ui/src/components/context_menu.rs

@@ -357,7 +357,7 @@ impl Render for ContextMenu {
                                                         .unwrap_or_else(|| {
                                                             KeyBinding::for_action(&**action, cx)
                                                         })
-                                                        .map(|binding| div().ml_1().child(binding))
+                                                        .map(|binding| div().ml_4().child(binding))
                                                 })),
                                         )
                                         .on_click(move |_, cx| {