Fix panic when hovering string ending with unicode (#38818)

Release Notes:

- Fixed a panic when hovering a string literal ending with an emoji

crates/editor/src/hover_links.rs

@@ -1862,4 +1862,42 @@ mod tests {
         cx.simulate_click(screen_coord, Modifiers::secondary_key());
         cx.update_workspace(|workspace, _, cx| assert_eq!(workspace.items(cx).count(), 1));
     }
+
+    #[gpui::test]
+    async fn test_hover_unicode(cx: &mut gpui::TestAppContext) {
+        init_test(cx, |_| {});
+        let mut cx = EditorLspTestContext::new_rust(
+            lsp::ServerCapabilities {
+                ..Default::default()
+            },
+            cx,
+        )
+        .await;
+
+        cx.set_state(indoc! {"
+            You can't open ˇ\"🤩\" because it's an emoji.
+        "});
+
+        // File does not exist
+        let screen_coord = cx.pixel_position(indoc! {"
+            You can't open ˇ\"🤩\" because it's an emoji.
+        "});
+        cx.simulate_mouse_move(screen_coord, None, Modifiers::secondary_key());
+
+        // No highlight, does not panic...
+        cx.update_editor(|editor, window, cx| {
+            assert!(
+                editor
+                    .snapshot(window, cx)
+                    .text_highlight_ranges::<HoveredLinkState>()
+                    .unwrap_or_default()
+                    .1
+                    .is_empty()
+            );
+        });
+
+        // Does not open the directory
+        cx.simulate_click(screen_coord, Modifiers::secondary_key());
+        cx.update_workspace(|workspace, _, cx| assert_eq!(workspace.items(cx).count(), 1));
+    }
 }