Treat first argument of static method call as `this`

[iirekm]

So for example substringAfter(string, ".") becomes string.substringAfter(".") just like in Kotlin for example

[lppedd]

@iirekm that MUST be implemented somehow! Great idea

[ciscorucinski]

This should allow for using nullable annotations to create correct Kotlin-like types. However, if there is no annotation, then it should be converted to a nullable type by default when it is folded. That will allow developers to add the correct nullable annotations.