Dont run lint ci in docs

What does this MR do?

The lint-ci-gitlab job was picking up a few warnings for comments, so I fixed them: https://gitlab.com/gitlab-org/gitlab/-/jobs/816021801.

It also sets the job to only run when CI YAML files are changed, because it seems like this job is meant for that, and it shouldn't run when we are changing Vale config files in /doc (which are also yaml files).

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team