meta. mark types as deprecated to simplify the cleanup

src/entt/meta/factory.hpp

@@ -98,7 +98,7 @@ protected:
         }
     }
 
-    void prop(meta_prop_node node) {
+    [[deprecated("use ::custom() instead")]] void prop(meta_prop_node node) {
         std::vector<meta_prop_node> *container = nullptr;
 
         if(bucket == parent) {

src/entt/meta/meta.hpp

@@ -765,7 +765,7 @@ private:
 };
 
 /*! @brief Opaque wrapper for properties of any type. */
-struct meta_prop {
+struct [[deprecated("use meta_custom instead")]] meta_prop {
     /*! @brief Default constructor. */
     meta_prop() noexcept = default;
 

src/entt/meta/node.hpp

@@ -67,7 +67,7 @@ struct meta_custom_node {
     std::shared_ptr<void> value{};
 };
 
-struct meta_prop_node {
+struct [[deprecated("no longer required")]] meta_prop_node {
     id_type id{};
     meta_type_node (*type)(const meta_context &) noexcept {};
     std::shared_ptr<void> value{};