[Issue 13656] clarify error message upon trying to declare a variable of type ref

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13656

--- Comment #2 from Shriramana Sharma <samjnaa at gmail.com> ---
Hmm... I seemed to have filed bug 13655 separately, but it's closely related to
this one.

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