Properly score fuzzy match queries with multiple chars in lower case (#29794)

Closes https://github.com/zed-industries/zed/issues/29526

Release Notes:

- Fixed file finder crashing for certain file names with multiple chars
in lowercase form

crates/file_finder/src/file_finder_tests.rs

@@ -242,6 +242,38 @@ async fn test_matching_paths(cx: &mut TestAppContext) {
     }
 }
 
+#[gpui::test]
+async fn test_unicode_paths(cx: &mut TestAppContext) {
+    let app_state = init_test(cx);
+    app_state
+        .fs
+        .as_fake()
+        .insert_tree(
+            path!("/root"),
+            json!({
+                "a": {
+                    "İg": " ",
+                }
+            }),
+        )
+        .await;
+
+    let project = Project::test(app_state.fs.clone(), [path!("/root").as_ref()], cx).await;
+
+    let (picker, workspace, cx) = build_find_picker(project, cx);
+
+    cx.simulate_input("g");
+    picker.update(cx, |picker, _| {
+        assert_eq!(picker.delegate.matches.len(), 1);
+    });
+    cx.dispatch_action(SelectNext);
+    cx.dispatch_action(Confirm);
+    cx.read(|cx| {
+        let active_editor = workspace.read(cx).active_item_as::<Editor>(cx).unwrap();
+        assert_eq!(active_editor.read(cx).title(cx), "İg");
+    });
+}
+
 #[gpui::test]
 async fn test_absolute_paths(cx: &mut TestAppContext) {
     let app_state = init_test(cx);