Panel scroll information

• rel_x - content scrolled position (0.0 ~ 1.0) in the panel
• rel_y - content scrolled position (0.0 ~ 1.0) in the panel

struct Efl.Ui.Panel_Scroll_Info {
    rel_x: double;
    rel_y: double;
}

typedef struct _Efl_Ui_Panel_Scroll_Info {
    double rel_x;
    double rel_y;
} Efl_Ui_Panel_Scroll_Info;