[RFR] Fix missing documentation for ra-data-fakerest logging abilities

[fzaninotto]

Pass true as second argument to log the requests made to the provider in the console. This is very helpful to debug the requests made by an app using this data provider.

// in src/App.js
import React from 'react';
import { Admin, Resource } from 'react-admin';
import fakeDataProvider from 'ra-data-fakerest';

const dataProvider = fakeDataProvider({ /* data here */ }, true);

const App = () => (
    <Admin dataProvider={dataProvider}>
        // ...
    </Admin>
);