Remove default "@returns" for constructors

[VoidVolker]

By default constructor returns and current class instance. If constructor returns any value - add docs.

[kimlimjustin]

I don't think this is possible to detect whether a function is a constructor except by creating an intellisense, but I want to keep this extension lightweight. However, I'll just detect if the line contains the word constructor and if it is, I'll just remove the default "@returns".

However, if you get any ideas, any PR will be welcomed :)