Add city range tutorial.

android/assets/jsons/Tutorials_English.json

@@ -306,5 +306,13 @@
 			"Units are defenseless while embarked, so be careful!"
 		]
 	]
+
+	CityRange:[
+		[
+			"Your citizens can work 3 tiles away from city center.",
+			"The city border will keep expanding,",
+			"But citizen cannot be assigned to a tile too far."
+		]
+	]
 	
 }

core/src/com/unciv/ui/cityscreen/CityScreen.kt

@@ -60,6 +60,10 @@ class CityScreen(internal val city: CityInfo) : CameraStageBaseScreen() {
         updateGoToWorldButton()
         updateTileTable()
         updateTileGroups()
+
+        if (city.getCenterTile().getTilesAtDistance(4).isNotEmpty()){
+            displayTutorials("CityRange")
+        }
     }
 
     private fun updateTileGroups() {