The documentation for ColPivHouseholderQR appears to be missing from the generated documentation. This is the only decomposition that lacks its documentation once processed by doxygen for some reason (cf. http://eigen.tuxfamily.org/dox-devel/group__TopicLinearAlgebraDecompositions.html or http://eigen.tuxfamily.org/dox/group__TopicLinearAlgebraDecompositions.html). I was able to reproduce this locally.
Should be fixed in devel and 3.2 branch: