How do you populate the Xcode 4 “Option+Click” popover?

Question

In Xcode 4, if you option + click on a keyword, then the said keyword will appear in a popover with a bunch of descriptive information, like so:

Answer 1

You must create your own "documentation set" for your API. Search Xcode's documentation for "Documentation Set Guide" and dig in. The "Documentation Sets" section of the guide specifically states that Quick Help uses this.

With a doc set in place, not only will this popup find the description but it will be available in the QuickHelp in the Utility pane as well as the documentation browser in the Organizer.