refactor(example): ref qualifiers added to a conversion operator of validated_type

example/include/validated_type.h

@@ -61,12 +61,17 @@ public:
   {
   }
 
-  constexpr explicit(false) operator T() const noexcept(std::is_nothrow_copy_constructible_v<T>)
+  constexpr explicit(false) operator T() const & noexcept(std::is_nothrow_copy_constructible_v<T>)
     requires std::copyable<T>
   {
     return value_;
   }
 
+  constexpr explicit(false) operator T() && noexcept(std::is_nothrow_move_constructible_v<T>)
+  {
+    return std::move(value_);
+  }
+
   constexpr T& value() & noexcept = delete;
   constexpr const T& value() const& noexcept { return value_; }
   constexpr T&& value() && noexcept { return std::move(value_); }