Function interp_grid_show_layout 

fn interp_grid_show_layout(
    args: &[RValue],
    _named: &[(String, RValue)],
    context: &BuiltinContext<'_>,
) -> Result<RValue, RError>

Visualize a grid layout by drawing labeled rectangles for each cell.

@param layout a layout object to visualize @return NULL (invisibly)