dip1000 return scope dmd v 2.100

[vit]

Hello, new dmd (2.100) has return/scope changes.
It look like examples at page 
https://dlang.org/spec/function.html#ref-return-scope-parameters 
are no longer relevant.

What difference are between `return scope`, `scope return` and 
`return`?
Why `void* ptr` in struct change effect of `scope return` ?


```d
@safe:

struct A{
	int  val;
	//void* ptr;

	int* test() scope return{
		return &this.val;	// OK
	}
}

struct B{
	int  val;
	void* ptr;

	int* test() return{
		return &this.val; // OK
	}
}

struct C{
	int  val;
	void* ptr;

	int* test() scope return{
		return &this.val; // Error: returning `&this.val` escapes a 
reference to parameter `this`
	}
}


void main(){}
```