Proper RTL support (#1154)

* Add RTL styles. Most of the work is done by the browser 💖

* Refactor getLanguage

* Additional fixes

* Mirror the mouse pointer icon

* Move the vertical scrollbar to the left on RTL

* Revert "Mirror the mouse pointer icon"

This reverts commit f69b132538038d231b1b1acc0d6f4a28c91130bb.

src/element/textWysiwyg.tsx

@@ -43,6 +43,7 @@ export function textWysiwyg({
   } catch {
     editable.contentEditable = "true";
   }
+  editable.dir = "auto";
   editable.tabIndex = 0;
   editable.innerText = initText;
   editable.dataset.type = "wysiwyg";