Better clarify map_to_world() description

doc/classes/TileMap.xml

@@ -202,7 +202,8 @@
 			<return type="Vector2" />
 			<argument index="0" name="map_position" type="Vector2i" />
 			<description>
-				Returns the local position corresponding to the given tilemap (grid-based) coordinates.
+				Returns a local position of the center of the cell at the given tilemap (grid-based) coordinates.
+				[b]Note:[/b] This doesn't correspond to the visual position of the tile, i.e. it ignores the [member TileData.texture_offset] property of individual tiles.
 			</description>
 		</method>
 		<method name="move_layer">

scene/2d/tile_map.cpp

@@ -2725,7 +2725,7 @@ void TileMap::_get_property_list(List<PropertyInfo> *p_list) const {
 }
 
 Vector2 TileMap::map_to_world(const Vector2i &p_pos) const {
-	// SHOULD RETURN THE CENTER OF THE TILE
+	// SHOULD RETURN THE CENTER OF THE CELL
 	ERR_FAIL_COND_V(!tile_set.is_valid(), Vector2());
 
 	Vector2 ret = p_pos;