- make codemirror package more capable

- add themes from react package
- add Autocomplete from react package
- handle dynamic extensions
- handle keyboard shortcuts
- make StrudelMirror as capable as Repl

packages/codemirror/flash.mjs

@@ -33,3 +33,5 @@ export const flash = (view, ms = 200) => {
     view.dispatch({ effects: setFlash.of(false) });
   }, ms);
 };
+
+export const isFlashEnabled = (on) => (on ? flashField : []);