fix cli app help.

cmd/lucy/help.go

@@ -10,7 +10,7 @@ EXAMPLES
 DEVICE COMMANDS
   list <search>
   set <search> <power=B> <color=C> <intensity=F> <temperature=N>
-  tag <search> <[+/-]tag-name> –-Tag
+  tag <search> <[+/-]tag-name>
   update <search> <name=S> <icon=S> <prop.*=S/NULL>
 
 EVENT COMMANDS