[ip6] update documentation for otIp6ReceiveCallback (#3584)
[ip6] update documentation for otIp6ReceiveCallback (#3584)


chshu/openthread,abtink/openthread,chshu/openthread,openthread/openthread,chshu/openthread,librasungirl/openthread,chshu/openthread,jwhui/openthread,srickardti/openthread,librasungirl/openthread,srickardti/openthread,lanyuwen/openthread,lanyuwen/openthread,bukepo/openthread,bukepo/openthread,abtink/openthread,srickardti/openthread,lanyuwen/openthread,turon/openthread,jwhui/openthread,srickardti/openthread,chshu/openthread,lanyuwen/openthread,turon/openthread,chshu/openthread,lanyuwen/openthread,turon/openthread,turon/openthread,openthread/openthread,librasungirl/openthread,abtink/openthread,openthread/openthread,bukepo/openthread,bukepo/openthread,librasungirl/openthread,jwhui/openthread,abtink/openthread,openthread/openthread,jwhui/openthread,lanyuwen/openthread