Bug: message#channel still returns old TextChannel instance after change to news type channel

[almostSouji]

Please describe the problem you are having in as much detail as possible:

message#channel still returns old TextChannel instance after change to news type channel

Include a reproducible code sample here, if possible:

1. create a text channel
2. make it a news channel (can be manual through GUI)
3. get <Message>.channel inside this (now news) channel

observe: you get a TextChannel of type GUILD_TEXT
reason:

discord.js/src/client/actions/ChannelUpdate.js

Lines 15 to 19 in cd47a52

	if (ChannelTypes[channel.type] !== data.type) {
	const newChannel = Channel.create(this.client, data, channel.guild);
	for (const [id, message] of channel.messages.cache) newChannel.messages.cache.set(id, message);
	this.client.channels.cache.set(channel.id, channel);
	}

we do transfer the messages to the new channel, however, each message still has the old channel (due to Message#channel not being a getter but a value)

Further details:

• discord.js version: 328501b
• Node.js version: 16.5
• Operating system: n/a
• Priority this issue should have – please be realistic and elaborate if possible: medium

Relevant client options:

• partials: n/a
• gateway intents: GUILDS, GUILD_MESSAGES
• other: n/a

[almostSouji]

The most straight-forward and least hacky solution I can think of would be to make Message#channel a getter which retrieves this from cache instead. I can't find any reason so far why this would benefit from being a fix value vs. a getter

Alternatively this could be addressed by iterating over the message cache and setting the new channel to each message (though that seems to be quite the elaborate and hacky work-around)