*NEVER* call macro inside translatable strings,

...it won't work if a transation is used.

TODO: there is some others in
data/multiplayer/scenarios/ANL_utils/ANL_leader_options.cfg to fix
(trickier because it's [message] child macros)

data/multiplayer/scenarios/ANL_utils/ANL_general_macros.cfg

@@ -68,11 +68,18 @@
     image=items/chest-plain-closed.png
     [/removeitem]
 {PLACE_IMAGE items/chest-plain-open.png {X} {Y}}
+[set_variable]
+    name=oc_treasure
+    value={TREASURE}
+[/set_variable]
 [message]
     speaker=narrator
     image=items/chest-plain-open.png
-    message= _ "The chest contains {TREASURE} gold."
+    message= _ "The chest contains $oc_treasure gold."
 [/message]
+[clear_variable]
+    name=oc_treasure
+[/clear_variable]
 {ADD_GOLD $side_number {TREASURE}}
 #enddef