code: func (v *ToolItem) SetTooltipText(text string) {
  	cstr := C.CString(text)
  	defer C.free(unsafe.Pointer(cstr))
  	C.gtk_tool_item_set_tooltip_text(v.native(), (*C.gchar)(cstr))
  }
docs: // SetTooltipText is a wrapper around gtk_tool_item_set_tooltip_text().