Sets the area of the widget, where the contents of this tooltip apply, to be rect (in widget coordinates).
This is especially useful for properly setting tooltips on `GtkTreeView` rows and cells, `GtkIconViews`, etc.
For setting tooltips on `GtkTreeView`, please refer to the convenience functions for this: set_tooltip_row and set_tooltip_cell.
| this |
a `GtkTooltip` |
| rect |
a `GdkRectangle` |