docs: explain scanner bucket quota check process

Community Contribution License

All community contributions in this pull request are licensed to the project maintainers under the terms of the Apache 2 license. By creating this pull request I represent that I have the right to license the contributions to the project maintainers under the Apache 2 license.

Description

Proposed addition to mc quota set help to clarify that bucket quotas are only checked at the time of a scanner pass. Discussion on what exactly this text should say is very welcome.

Motivation and Context

The current docs (mc help, web) don't describe the role of the scanner in determining the quota status. Since the scanner only runs periodically, a bucket can exceed its quota until the next scanner pass notices.

In my opinion we should also not describe this as a "hard quota." That suggests MinIO will never allow writes beyond the configured quota, which is incorrect.

How to test this PR?

Docs only change (mc quota set help text)

Types of changes

[ ] Bug fix (non-breaking change which fixes an issue)
[ ] New feature (non-breaking change which adds functionality)
[ ] Optimization (provides speedup with no functional changes)
[ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

[ ] Fixes a regression (If yes, please add commit-id or PR # here)
[ ] Unit tests added/updated
[ ] Internal documentation updated
[ ] Create a documentation update request here

minio / mc