Add scan related events documentation
Add scan related events documentation

cloverstd/wechatpy,messense/wechatpy,hunter007/wechatpy,cloverstd/wechatpy,zaihui/wechatpy,jxtech/wechatpy,zhaoqz/wechatpy,wechatpy/wechatpy,hunter007/wechatpy,zhaoqz/wechatpy,zaihui/wechatpy