Update doc

mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/internal/MessageDataInternal.kt

@@ -118,7 +118,7 @@ fun ByteReadPacket.readMessageChain(): MessageChain {
 }
 
 fun MessageChain.toPacket(): ByteReadPacket = buildPacket {
-    this@toPacket.list.forEach { message ->
+    this@toPacket.forEach { message ->
         writePacket(with(message) {
             when (this) {
                 is Face -> buildPacket {

mirai-core/src/commonMain/kotlin/net.mamoe.mirai/network/protocol/tim/packet/Packet.kt

@@ -5,6 +5,9 @@ package net.mamoe.mirai.network.protocol.tim.packet
 import net.mamoe.mirai.utils.hexToUBytes
 
 
+/**
+ * 数据包
+ */
 abstract class Packet {
     open val idHex: String by lazy {
         this::class.annotations.filterIsInstance<PacketId>().firstOrNull()?.value?.trim() ?: ""

mirai-core/src/commonMain/kotlin/net.mamoe.mirai/network/protocol/tim/packet/ServerPacket.kt

@@ -9,6 +9,9 @@ import kotlinx.io.core.readBytes
 import net.mamoe.mirai.utils.*
 
 
+/**
+ * 来自服务器的数据包
+ */
 abstract class ServerPacket(val input: ByteReadPacket) : Packet(), Closeable {
     override var idHex: String = EMPTY_ID_HEX
         get() {