Clarify rc_room_creation configuration documentation - conflicting information about per_user parameter

[sidm-finno]

Summary

The documentation for rc_room_creation contains conflicting information about whether the per_user parameter is supported, making it unclear how to properly configure room creation rate limits.

Issue Details

The rate limiting configuration documentation shows contradictory examples:

Default configuration (includes per_user):

rc_room_creation:
  per_user:
    per_second: 0.016
    burst_count: 10.0

Example configuration (excludes per_user):

rc_room_creation:
  per_second: 1.0
  burst_count: 5.0

The documentation doesn't explain what the per_user parameter does or when it should be used. Looking at the source code, the default configuration doesn't appear to be defined with per_user

Questions

1. Is per_user a valid/supported parameter for rc_room_creation?
2. If yes, what is the behavior difference between using per_user and not using it?
3. What is the correct way to configure room creation rate limits?
4. Should the documentation be updated to clarify this?

Expected Outcome

Clear documentation that explains:

• Whether per_user is supported for rc_room_creation
• What per_user does (if supported)
• Consistent examples that match the actual default configuration
• Clear guidance on how to increase room creation rate limits

[velikopter]

I believe #18998 resolves this?

[sidm-finno]

Yes, it does. I think we can mark this one resolve.