Fix: Return rvalue-ref to stored_ in rref-qualified deref-operators

[vector-of-bool]

result::value() correctly returns std::move(stored_), but operator* simply returns value(), which will always call the lref-qualified value(), and incorrectly attempt to bind the returned (lvalue reference) to an rvalue reference.

This change calls move(*this) for an rvalue call to value()

[zajo]

Thank you! I should add unit tests for this.