stop encouraging to ask about opening hours

app/src/main/res/values/strings.xml

@@ -453,7 +453,7 @@ Otherwise, you can download another keyboard in the app store. Popular keyboards
     <string name="invalidate_confirmation">Invalidate</string>
     <string name="invalidation_dialog_message">Invalidating the cache causes the quests to be updated next time they are downloaded. The quest cache is invalidated automatically after one week and immediately when a quest you solved turns out to be already answered by someone else.</string>
     <string name="quest_openingHours_emptyAnswer">You need to describe what is on the sign. If there is no sign, you should ask for the opening hours inside.</string>
-    <string name="quest_openingHours_no_sign">Opening hours are unknown</string>
+    <string name="quest_openingHours_no_sign">No opening hours sign</string>
     <string name="quest_openingHours_answer_noSign_confirmation_title">Are you sure that there is no sign with opening hours info?</string>
     <string name="quest_openingHours_noSign_confirmation_positive">Yes, no sign.</string>
     <string name="quest_cycleway_value_none_but_no_oneway">none, but cyclists may use road in both directions</string>