Replace `GatewayIntent#GUILD_EMOJIS_AND_STICKERS` with `GUILD_EXPRESSIONS`

[freya022]

Pull Request Etiquette

• [X] I have checked the PRs for upcoming features/bug fixes.
• [X] I have read the contributing guidelines.

Changes

• [ ] Internal code
• [X] Library interface (affecting end-user code)
• [X] Documentation
• [ ] Other: _____

Closes Issue: NaN

Description

Updates the intent to match Discord's name, will be clearer for #2753

If the user does not migrate to the new intent, and has activated cache flags that require the GUILD_EXPRESSIONS intents, the cache flags will get disabled and a warning will be logged.