add link to documentation page
add link to documentation page

robertodr/xcfun,bast/xcfun,bast/xcfun,dftlibs/xcfun,robertodr/xcfun,robertodr/xcfun,dftlibs/xcfun,dftlibs/xcfun,dftlibs/xcfun,bast/xcfun,bast/xcfun,robertodr/xcfun