Adds ServerVariableToRequestFacadeRector rule

[peterfox]

Changes

• new ServerVariableToRequestFacadeRector rule
• adds tests
• updates docs

Why

This converts a simple use of the $_SERVER PHP variable to use the Request facade.

-$_SERVER['VARIABLE'];
+\Illuminate\Support\Facade\Request::server('VARIABLE');

[GeniJaho]

@peterfox Are there any similar cases to the other PR of the $_SESSION global? I think we can include more cases in this rule, with a similar implementation.

[peterfox]

Nothing I can think of. I need to look at getallheaders but I'm not sure how 1:1 that is.

I think the only thing is possibly some key values such as:

$_SERVER['HTTP_USER_AGENT'];
$_SERVER['REQUEST_METHOD'];

Would be better replaced by dedicated method calls. That might be better off with a dedicated rule though, so you'd apply this rule and then one to transform \Illuminate\Support\Facade\Request::server('HTTP_USER_AGENT') into \Illuminate\Support\Facade\Request::userAgent().