Improve documentation for Code Owners

I just read documentation for Code Owners (https://docs.gitlab.com/ee/user/project/code_owners.html), and I feel it takes too much to me to understand what the feature is for.

I mean, it describes all the setup, but I feel it misses a clear explanation of the output. The only sentence (barely missed during my fast-reading) related to that is:

When a file matches multiple entries in the CODEOWNERS file, the users from all entries are displayed on the blob page of the given file.

I think I would be super-easy for me to better grab the feature if something like https://gitlab.com/gitlab-org/gitlab-ee/uploads/aa5dcc0deaf7472ec1b7a04549d23261/code-owners.png is added to the documentation page. Probably there is no need to read any sentence if you are just looking to the "consumer" part of the feature 🙂