Ensure hunk controls have unique element ids (#23815)

This fixes an edge case when two hunk controls button groups were
visible (due to having text cursor on one hunk, and mouse cursor on the
other). In that situation, the mouse states for the two button groups
would mirror.

Release Notes:

- N/A

crates/editor/src/element.rs

@@ -3829,8 +3829,13 @@ impl EditorElement {
                         - scroll_pixel_position.y;
                     let x = text_hitbox.bounds.right() - px(100.);
 
-                    let mut element =
-                        diff_hunk_controls(multi_buffer_range.clone(), line_height, &editor, cx);
+                    let mut element = diff_hunk_controls(
+                        display_row_range.start.0,
+                        multi_buffer_range.clone(),
+                        line_height,
+                        &editor,
+                        cx,
+                    );
                     element.prepaint_as_root(
                         gpui::Point::new(x, y),
                         size(px(100.0), line_height).into(),
@@ -8524,6 +8529,7 @@ mod tests {
 }
 
 fn diff_hunk_controls(
+    row: u32,
     hunk_range: Range<Anchor>,
     line_height: Pixels,
     editor: &Entity<Editor>,
@@ -8541,7 +8547,7 @@ fn diff_hunk_controls(
         .bg(cx.theme().colors().editor_background)
         .gap_1()
         .child(
-            IconButton::new("next-hunk", IconName::ArrowDown)
+            IconButton::new(("next-hunk", row as u64), IconName::ArrowDown)
                 .shape(IconButtonShape::Square)
                 .icon_size(IconSize::Small)
                 // .disabled(!has_multiple_hunks)
@@ -8564,7 +8570,7 @@ fn diff_hunk_controls(
                 }),
         )
         .child(
-            IconButton::new("prev-hunk", IconName::ArrowUp)
+            IconButton::new(("prev-hunk", row as u64), IconName::ArrowUp)
                 .shape(IconButtonShape::Square)
                 .icon_size(IconSize::Small)
                 // .disabled(!has_multiple_hunks)