Inset ContextMenu headers (#9197)

This PR insets the headers within `ContextMenu`s to give them some more
breathing room.

#### Before

<img width="347" alt="Screenshot 2024-03-11 at 4 13 31 PM"
src="https://github.com/zed-industries/zed/assets/1486634/73a56d68-d40e-4396-b584-f443197b69d6">

#### After

<img width="354" alt="Screenshot 2024-03-11 at 4 12 43 PM"
src="https://github.com/zed-industries/zed/assets/1486634/44c12a07-0784-4c94-b194-245f5cf94b2b">

Release Notes:

- Added padding to headers in context menus.

crates/ui/src/components/context_menu.rs

@@ -272,11 +272,12 @@ impl Render for ContextMenu {
                 })
                 .flex_none()
                 .child(List::new().children(self.items.iter_mut().enumerate().map(
-                    |(ix, item)| match item {
+                    |(ix, item)| {
+                        match item {
                             ContextMenuItem::Separator => ListSeparator.into_any_element(),
-                        ContextMenuItem::Header(header) => {
-                            ListSubHeader::new(header.clone()).into_any_element()
-                        }
+                            ContextMenuItem::Header(header) => ListSubHeader::new(header.clone())
+                                .inset(true)
+                                .into_any_element(),
                             ContextMenuItem::Entry {
                                 label,
                                 handler,
@@ -317,7 +318,9 @@ impl Render for ContextMenu {
                                                 self.action_context
                                                     .as_ref()
                                                     .map(|focus| {
-                                                    KeyBinding::for_action_in(&**action, focus, cx)
+                                                        KeyBinding::for_action_in(
+                                                            &**action, focus, cx,
+                                                        )
                                                     })
                                                     .unwrap_or_else(|| {
                                                         KeyBinding::for_action(&**action, cx)
@@ -347,6 +350,7 @@ impl Render for ContextMenu {
                                     .child(entry_render(cx))
                                     .into_any_element()
                             }
+                        }
                     },
                 ))),
         )

crates/ui/src/components/list/list_sub_header.rs

@@ -21,6 +21,11 @@ impl ListSubHeader {
         self.start_slot = left_icon;
         self
     }
+
+    pub fn inset(mut self, inset: bool) -> Self {
+        self.inset = inset;
+        self
+    }
 }
 
 impl RenderOnce for ListSubHeader {