Include exceptions within API reference

[No767]

Summary

Previous exceptions were not documented, so this is a change in order to have them documented instead.

Types of changes

What types of changes does your code introduce to discord-ext-ipcx?
Put an x in the boxes that apply

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (Updates to README.md, the documentation, etc)
• Other (if none of the other choices apply)

Checklist

Put an x in the boxes that apply

• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes. (if appropriate)
• All workflows pass with my new changes
• I have generated news fragments for this PR. (if appropriate, format is {#PR}.type.md)
• This PR does not address a duplicate issue or PR