Updated FromFile() to remove unused TextureRegion (#193)

Removed redundant TextureRegion region because it's not used in the Method.

Author: jordanlhunt

articles/tutorials/building_2d_games/13_working_with_tilemaps/snippets/tilemap.cs

@@ -230,9 +230,6 @@ public static Tilemap FromFile(ContentManager content, string filename)
                         // Get the tileset index for this location
                         int tilesetIndex = int.Parse(columns[column]);
 
-                        // Get the texture region of that tile from the tileset
-                        TextureRegion region = tileset.GetTile(tilesetIndex);
-
                         // Add that region to the tilemap at the row and column location
                         tilemap.SetTile(column, row, tilesetIndex);
                     }