Adds missing shortcuts to TileEditor. Keeps fill-tool selected after use

The following keyboard shortcuts are now available:
-Bucket fill (G)
-Paint Tile (P)
-Transpose Tile (T)
Fixes #10918

editor/plugins/tile_map_editor_plugin.h

@@ -68,7 +68,8 @@ class TileMapEditor : public VBoxContainer {
 		OPTION_PICK_TILE,
 		OPTION_SELECT,
 		OPTION_DUPLICATE,
-		OPTION_ERASE_SELECTION
+		OPTION_ERASE_SELECTION,
+		OPTION_PAINTING,
 	};
 
 	TileMap *node;