Add documentation for mapping based on VOMS attribute
Add documentation for mapping based on VOMS attribute

And some rewording of the other comments

matyasselmeci/htcondor-ce,opensciencegrid/htcondor-ce,djw8605/htcondor-ce,djw8605/htcondor-ce,brianhlin/htcondor-ce,matyasselmeci/htcondor-ce,brianhlin/htcondor-ce,opensciencegrid/htcondor-ce,opensciencegrid/htcondor-ce,brianhlin/htcondor-ce,djw8605/htcondor-ce,matyasselmeci/htcondor-ce