cpp/experimental/unique resource/reset

@1@ Disposes the resource by calling the deleter with the underlying resource handle if the owns it. The does not own the resource after the call. @2@ Replaces the resource by calling and then assigns the stored resource handle with  if  is, otherwise , where  is the type of stored resource handle. The owns the resource after the call. @@ If copy-assignment of the store resource handle throws an exception, calls, where is the deleter object. @@ . @@ The program is ill-formed if is ill-formed. @@ The behavior is undefined if results in undefined behavior or throws an exception.

Return value
(none)

Exceptions
@2@ Any exception thrown in assigning the stored resource handle.