Improve overriding stages example

What does this MR do?

Updates a troubleshooting entry that corresponds to errors running security jobs when the test stage name is missing.

For the default security jobs, the current examples appear dated for situations where the test stage is undefined. It is also lacking example names to use for all the (currently, 4) types of includes available.

This change adds a more complete example on how to override the stage name for every one of the included jobs, in a copy-paste-able form.

The updated job names used in the change are derived from the template files, using the highest inherited definitions so it can influence all jobs that arrive through the include statement.

Related issues

Customer ticket (Zendesk, internal link)

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