docs: Refactor a few @returns descriptions

[Jiralite]

Please describe the changes this PR makes and why it should be merged:
This pull request tweaks some @returns descriptions that I have judged... strange.

When I was looking through the documentation for a GuildEmoji, I noticed the GuildEmoji#equals() method had a @returns description on it. I also noticed the description is quite literally the same as the initial description. So like, why is it there? This is the same for Sticker#equals(), but there does not appear to be a @returns description for other equal() methods around discord.js such as User#equals() or Role#equals(). I went ahead and removed the two instances that had @returns descriptions for also the sake of being consistent.

TextChannel#createWebhook() had a @returns description of "webhook The created webhook". Obviously the first word shouldn't be there, but I altered this nonetheless to "Returns the created Webhook" to provide a better feedback description.

I also saw TextChannel#bulkDelete() just say "Deleted messages", so I thought it would be better to provide a better feedback description here also.

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 only includes non-code changes, like changes to documentation, README, etc.