Add support for tutorial links to makerst.py

Also change the <tutorials> structure to make use of individual <link> tags

doc/classes/InputMap.xml

@@ -7,7 +7,7 @@
 		Manages all [InputEventAction] which can be created/modified from the project settings menu [code]Project > Project Settings > Input Map[/code] or in code with [method add_action] and [method action_add_event]. See [method Node._input].
 	</description>
 	<tutorials>
-		http://docs.godotengine.org/en/3.0/tutorials/inputs/inputevent.html#inputmap
+		<link>http://docs.godotengine.org/en/3.0/tutorials/inputs/inputevent.html#inputmap</link>
 	</tutorials>
 	<demos>
 	</demos>