Added 'properties' to docs for 'Interface'.

Added code example to show how to use 'Property' in an Interface (Property with Setter, Getter, Setter+Getter).

modules/monkey/newdocs/language/user-types.md

@@ -66,10 +66,27 @@ To declare an interface:
 
 _Interfaces_ is a comma separated list of interface types.
 
-An interface can contain consts, globals, methods, functions and other user defined types.
+An interface can contain consts, globals, methods, functions, properties and other user defined types.
 
 Interface methods are always 'abstract' and cannot declare any code.
 
+Example for using properties in an interface:
+```
+Interface IExample
+
+	' Property with Setter
+	Property IntProp1( a:Int )
+
+	' Property with Getter
+	Property IntProp2:Int()
+
+	' Property with Setter + Getter
+	Property IntProp3:Int()
+	Setter( a:Int )
+
+End
+```
+
 
 @#### Fields