docs: fix change_presence function docs

[LawMixer]

Pull Request Type

• Feature addition
• Bugfix
• [ x ] Documentation update
• Code refactor
• Tests improvement
• CI/CD pipeline enhancement
• Other: [Replace with a description]

Description

This aligns change_presence function documentation to replica the recent addition of ActivityType.CUSTOM

Changes

• Fixed change_presence's function documentation to include custom

Related Issues

Test Scenarios

I tested via Visual Studio Code's Python extension and it worked on versions Python 3.10 and 3.11.

Python Compatibility

• [ x ] I've ensured my code works on Python 3.10.x
• [ x ] I've ensured my code works on Python 3.11.x

Checklist

• [ x ] I've run the pre-commit code linter over all edited files
• [ x ] I've tested my changes on supported Python versions
• [ x ] I've added tests for my code, if applicable
• [ x ] I've updated / added documentation, where applicable