Improve request input refactor

[peterfox]

Changes

• Improves some of the scenarios with the RequestVariablesToRequestFacadeRector rule. Namely it handles the split between get, post and request into the right method calls. Also handles replacing the whole variable.
• Adds tests for the scenario
• Docs update

Why

It makes this rule far more useful as a better 1:1 conversion of PHP to Laravel method calls on the Request facade.

-$_GET['value'];
-$_POST['value'];
-$_REQUEST['value'];
-$_POST;
-$_GET;
-$_REQUEST;
+\Illuminate\Support\Facades\Request::query('value');
+\Illuminate\Support\Facades\Request::post('value');
+\Illuminate\Support\Facades\Request::input('value');
+\Illuminate\Support\Facades\Request::query();
+\Illuminate\Support\Facades\Request::post();
+\Illuminate\Support\Facades\Request::all();