code: func (v *Entry) SetIconTooltipText(iconPos EntryIconPosition, tooltip string) {
  	cstr := C.CString(tooltip)
  	defer C.free(unsafe.Pointer(cstr))
  	C.gtk_entry_set_icon_tooltip_text(v.native(),
  		C.GtkEntryIconPosition(iconPos), (*C.gchar)(cstr))
  }
docs: // SetIconTooltipText() is a wrapper around gtk_entry_set_icon_tooltip_text().