Return outside function is allowed

[flofriday]

Example

Moose Interpreter (https://github.com/flofriday/Moose)
Written with <3 by Jozott00 and flofriday.
> return 23
ReturnSignal(value: 23)

This sholdn't be allowed and catched by the typechekcer.

[flofriday]

This is now fixed. I will add some tests to assure that it won't break in the future.