feat: support horizontal mouse scrolling in buffers

src/editor.rs

@@ -1735,6 +1735,14 @@ impl Editor {
         }
     }
 
+    pub(crate) fn scroll_diff_horizontal(&mut self, focus: Focus, right: bool, width: usize) {
+        if let Some(diff) = &mut self.diff
+            && diff.phase == Phase::View
+        {
+            diff.scroll_horizontal(focus, right, width);
+        }
+    }
+
     pub(crate) fn set_diff_viewport(
         &mut self,
         comparison_id: u64,