Improve handling of `unknown` permissions

[jsoref]

The current code is unhelpful for various reasons: https://github.com/GitHubSecurityLab/actions-permissions/blob/3dcbd6bb270cd62b67703a6c1aef904ace6a3bf3/monitor/index.js#L76-L77

1. It generates markdown with a workflow snippet like:

   Minimal required permissions:

   permissions:
     security-events: write
     pull-requests: read
     unknown: unknown
   

   But if someone were to add this permission, it'd result in the workflow failing:

2. It doesn't use at least ::warning or similar to call out the item https://github.com/jsoref/check-spelling/actions/runs/7331431111/job/19964051747#step:12:2

3. The grammar in the readme is off: https://github.com/GitHubSecurityLab/actions-permissions/blob/8ecfc0d800e75e5774f8eebc81b3f48f214b8ca4/monitor/README.md?plain=1#L62

   -It would requires parsing
   +It would require parsing
   

Expected results

1. Don't generate invalid workflow content
2. Do use # ... in the generated workflow content
3. Do surface the api call(s) -- if you're afraid of surfacing things, provide the client User-Agent, it should be possible to at least identify the objects being queried