added docs and fixed desc loading from item def

doc/en/item-properties.md

@@ -18,6 +18,14 @@ Name of the item model. The model will be loaded automatically.
 Default value is `packid:itemname.model`.
 If the model is not specified, an automatic one will be generated.
 
+### Caption and Description
+`caption` - name of item in inventory
+`description` - item description in inventory
+
+this props allow to use `md`
+
+*see [Text Styles](/doc/en/text-styles.md)*
+
 ## Behaviour
 
 ### *placing-block*

doc/en/scripting/builtins/libitem.md

@@ -10,6 +10,9 @@ item.index(name: str) -> int
 -- Returns the item display name.
 block.caption(blockid: int) -> str
 
+-- Returns the item display description.
+item.description(itemid: int) -> str
+
 -- Returns max stack size for the item
 item.stack_size(itemid: int) -> int