Webhook job event documentation should be updated
<!--
* Use this issue template for suggesting new docs or updates to existing docs.
Note: Doc work as part of feature development is covered in the Feature Request template.
* For issues related to features of the docs.gitlab.com site, see
https://gitlab.com/gitlab-org/gitlab-docs/issues/
* For information about documentation content and process, see
https://docs.gitlab.com/ee/development/documentation/ -->
### Problem to solve
<!-- Include the following detail as necessary:
* What product or feature(s) affected?
* What docs or doc section affected? Include links or paths.
* Is there a problem with a specific document, or a feature/process that's not addressed sufficiently in docs?
* Any other ideas or requests?
-->
As mentioned in https://gitlab.com/gitlab-com/account-management/commercial/netconomy/-/issues/14#note_742182791
the [webhooks documentation page](https://docs.gitlab.com/ee/user/project/integrations/webhook_events.htm) shows outdated schemas.
### Proposal
For each hook type, make sure the [schema in the docs](https://docs.gitlab.com/ee/user/project/integrations/webhook_events.html#push-events) matches the [sample schema](https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/data_builder/push.rb#L8-50) used for testing and the sample schema matches the actual schema.
- [ ] [Push events](https://gitlab.com/gitlab-org/gitlab/-/issues/347855)
- [ ] Tag event
- [ ] Issue event
- [ ] Comment event
- [ ] Merge request event
- [ ] Wiki page event
- [ ] Pipeline event
- [ ] Job event
- [ ] Deployment event
- [ ] Group member event
- [ ] Subgroup event
- [ ] Feature flag event
- [ ] Release event
epic