Users are confused from unsupported plurals in Simple format

[JanCizmar]

Users were repeatedly asking about the unsupported plurals when they follow our docs.

One was reporting this error:

I suggest

1. to add comment to all integrations like this

import { Tolgee, DevTools, TolgeeProvider, FormatSimple } from "@tolgee/react";

const tolgee = Tolgee()
  .use(DevTools())
   // replace with .use(FormatIcu()) for rendering plurals, foramatted numbers, etc.
  .use(FormatSimple())
  .init({
    language: 'en',

    // for development
    apiUrl: process.env.VITE_APP_TOLGEE_API_URL,
    apiKey: process.env.VITE_APP_TOLGEE_API_KEY,

    // for production
    staticData: {
      ...
    }
  });

...

<TolgeeProvider
  tolgee={tolgee}
  fallback="Loading..." // loading fallback
>
  <App/>
</TolgeeProvider>

2. Add hint to the parsing error

Forgot to use FormatIcu to render ICU message syntax?

3. We should add multiple examples of valid messages to this doc page
   https://tolgee.io/js-sdk/formatting

4. They should be informed that they use multiple formaters in the same time.