add tooltip for sufficient mood in `act`

sugarcube/src/actions/act.tw

@@ -69,6 +69,7 @@
 			<<set _styleClass += ' mood disabled'>>
 			<<set _act_contents = ''>>
 		<<else>>
+			<<set _tooltip = 'Your mood is high enough (>='+_flags.mood+') to do this.'>>
 			<<set _styleClass += ' mood'>>
 		<</if>>
 	<</if>>