* Use in_progress workflow_job example, not queued
### tl;dr
This changes the example `workflow_job` payload to be an `in_progress` event instead of `queued` event.
### why
In #22174, I added some keys to the example workflow_job json. This was correct, but by adding non-null _values_, **I introduced a subtle bug**.
It's a bug because a `queued` workflow is—by definition—_not_ yet assigned to a runner. So all the `runner_*` attributes will be `null` in the real world.
After the workflow becomes `in_progress`, all the values are guaranteed to exist. So let's change the example to be an `in_progress` event, since it's a better example for documentation.
* Explain more about the runner_* attributes in "workflow_job_properties.md"
* Consistentize naming
Co-authored-by: Martin Lopes <martin389@github.com>
Co-authored-by: hubwriter <hubwriter@github.com>
