feat(Message): add ReplyMessageOptions for #reply

[iShibi]

Please describe the changes this PR makes and why it should be merged:

1. The options parameter for Message#reply has a replyTo field. This field later gets set to this inside the method. This begs the question that why even expose the replyTo option to the end-user at all in this case. This PR creates a new type ReplyMessageOptions that replaces MessageOptions parameter for Message#reply method. This new type for options has all the fields that are in MessageOptions except the replyTo field.

2. Docs show the default value for repliedUser in MessageMentionOptions as none, but Message#reply does ping the author of the referenced message by default. The PR also fixes that.

Status and versioning classification:

• Code changes have been tested against the Discord API, or there are no code changes
• I know how to update typings and have done so, or typings don't need updating
• This PR changes the library's interface (methods or parameters added)
• This PR includes breaking changes (methods removed or renamed, parameters moved or removed)

[iShibi]

Just wanna say that when this PR was first created it only removed the replyTo field. Then, Discord released the fail_if_not_exists option, which made it dependent on #5298. As, a result this PR won't work on its own and will need #5298 to be merged first. This will also help in overwriting the doc changes that were needed in that PR but are redundant because of the changes made here.

[iCrawl]

You'll need to rebase this now @iShibi

[iShibi]

Rebase done. I hope I did it correctly 🤞