Correct lua_api.txt docs related to meta (#5198)

doc/lua_api.txt

@@ -2815,7 +2815,7 @@ See `StorageRef`, `NodeMetaRef` and `ItemStackMetaRef`.
 
 ### `NodeMetaRef`
 Node metadata: reference extra data and functionality stored in a node.
-Can be gotten via `minetest.get_meta(pos)`.
+Can be obtained via `minetest.get_meta(pos)`.
 
 #### Methods
 * All methods in MetaDataRef
@@ -2823,7 +2823,14 @@ Can be gotten via `minetest.get_meta(pos)`.
 
 ### `ItemStackMetaRef`
 ItemStack metadata: reference extra data and functionality stored in a stack.
-Can be gotten via `item:get_meta()`.
+Can be obtained via `item:get_meta()`.
+
+#### Methods
+* All methods in MetaDataRef
+
+### `StorageRef`
+Mod metadata: per mod metadata, saved automatically.
+Can be obtained via `minetest.get_mod_storage()` during load time.
 
 #### Methods
 * All methods in MetaDataRef
@@ -2850,9 +2857,6 @@ Can be gotten via `minetest.get_node_timer(pos)`.
 * `is_started()`: returns boolean state of timer
     * returns `true` if timer is started, otherwise `false`
 
-### `StorageRef`
-This is basically a reference to a C++ `ModMetadata`
-
 ### `ObjectRef`
 Moving things in the game are generally these.
 
@@ -3100,8 +3104,9 @@ an itemstring, a table or `nil`.
 * `set_count(count)`: Returns boolean whether item was cleared
 * `get_wear()`: Returns tool wear (`0`-`65535`), `0` for non-tools.
 * `set_wear(wear)`: Returns boolean whether item was cleared
-* `get_metadata()`: Returns metadata (a string attached to an item stack).
-* `set_metadata(metadata)`: Returns true.
+* `get_meta()`: Returns ItemStackMetaRef. See section for more details
+* `get_metadata()`: (DEPRECATED) Returns metadata (a string attached to an item stack).
+* `set_metadata(metadata)`: (DEPRECATED) Returns true.
 * `clear()`: removes all items from the stack, making it empty.
 * `replace(item)`: replace the contents of this stack.
     * `item` can also be an itemstring or table.