Replace F extension with string interpolation

OpenRA.Mods.Common/Lint/CheckMapTiles.cs

@@ -19,7 +19,7 @@ namespace OpenRA.Mods.Common.Lint
 		public void Run(Action<string> emitError, Action<string> emitWarning, ModData modData, Map map)
 		{
 			foreach (var kv in map.ReplacedInvalidTerrainTiles)
-				emitError("Cell {0} references invalid terrain tile {1}.".F(kv.Key, kv.Value));
+				emitError($"Cell {kv.Key} references invalid terrain tile {kv.Value}.");
 		}
 	}
 }