Feature: Hint viewer (#666)

* Add Hint viewer

- Add hints for arrows and lines
- Add hints for resizing elements

* Swap priority of multi mode and resize mode in Hint Viewer

* Remove dangling locales from public

* Add shortcut to hide hints

* Change hint texts and show resize hint ONLY during resizing

* Remove hints toggling

src/types.ts

@@ -25,4 +25,5 @@ export type AppState = {
   scrolledOutside: boolean;
   name: string;
   selectedId?: string;
+  isResizing: boolean;
 };