Fix documentation for cppclass static methods.
Fix documentation for cppclass static methods.

Closes #1438.
ChristopherHogan/cython,cython/cython,cython/cython,da-woods/cython,fabianrost84/cython,da-woods/cython,scoder/cython,ChristopherHogan/cython,scoder/cython,fabianrost84/cython,scoder/cython,scoder/cython,da-woods/cython,fabianrost84/cython,cython/cython,da-woods/cython,fabianrost84/cython,ChristopherHogan/cython,cython/cython,fabianrost84/cython