Update Code Owners troubleshooting section

What does this MR do and why?

A customer recently asked why their directory does not show the expected Code Owners when viewing it directly, but the files beneath it are correct. They shared an example similar to the below:

* @group/infra @group/infosec
environments/staging/ @group/data

With this configuration, we see the following:

	Directory View. Shows that the '*' has been applied
	File View. Shows that the more-specific rule has been applied

The customer has administrative requirements that viewing a directory should show the appropriate 'owners' of the files beneath the directory. I've confirmed with Source Code team (expiring slack link) that the current behaviour is intentional, and the expected behaviour is to create an additional Code Owners rule like the following:

* @group/infra @group/infosec
environments/staging @group/data
environments/staging/ @group/data

This MR adds documentation to reflect this design choice and how to achieve the desired result.

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