[CMake] Improvements for cross-referencing in the documentation?

[SF Markus Elfring]

> Much to my surprise, there was only a single "CMAKE_MATCH" on our
> whole documentation page. It would make sense to document the variables
> CMAKE_MATCH_0 and friends explicitly. And cross-referencing left, right, north
> and south would also be good.

Does the current documentation format support detailed cross-referencing (with 
hyperlinks)?

Regards,
Markus