CMake 3.0 was released last week with many major new features and new Qt integration for uic and rcc. A major change with this CMake release is the new documentation system based on reStructuredText and Sphinx.
Sphinx has the ability to generate Qt Assistant files, so these are now easy to create reproducibly from the CMake source documentation. Generated qch documentation for CMake 3.0.0 is available here. Load it in QtCreator through the “Tools -> Options” menu item.
Of course, when the documentation is easily available in QtCreator, the next step is to access it while editing your CMake files. A simple patch to QtCreator will allow navigating to CMake documentation by clicking a command and pressing F1 as usual.