resource: discard the no longer necessary operator!=

src/entt/resource/resource.hpp

@@ -196,19 +196,6 @@ template<typename Lhs, typename Rhs>
     return (std::addressof(*lhs) == std::addressof(*rhs));
 }
 
-/**
- * @brief Compares two handles.
- * @tparam Lhs Type of resource managed by the first handle.
- * @tparam Rhs Type of resource managed by the second handle.
- * @param lhs A valid handle.
- * @param rhs A valid handle.
- * @return False if both handles refer to the same resource, true otherwise.
- */
-template<typename Lhs, typename Rhs>
-[[nodiscard]] bool operator!=(const resource<Lhs> &lhs, const resource<Rhs> &rhs) noexcept {
-    return !(lhs == rhs);
-}
-
 /**
  * @brief Compares two handles.
  * @tparam Lhs Type of resource managed by the first handle.