doc: update Multithreading documentation as embedded wasm isnt a requirement anymore

Author: peaBerberian

doc/api/Miscellaneous/MultiThreading.md

@@ -225,13 +225,10 @@ You can find it at any of the following places:
   import { EMBEDDED_WORKER } from "rx-player/experimental/features/embeds";
   ```
 
-  This allows to bypass the need to store and serve separately those two files.
+  This allows to bypass the need to store and serve separately that file.
 
   If you would prefer more control and a smaller bundle size, you may instead consider the
-  other following ways to load those as separate files. This will lead to smaller file
-  sizes and they will only be loaded on demand, but at a maintenance cost: you'll have to
-  store and serve those files yourself as well as not forget to update them each time you
-  update the RxPlayer.
+  other following ways to it as a separate file.
 
 - With every release note published on GitHub as `worker.js` (you should only use the file
   linked to the RxPlayer's version you're using),