Improved docstrings for MultiGroupXS
Improved docstrings for MultiGroupXS

samuelshaner/openmc,liangjg/openmc,smharper/openmc,walshjon/openmc,kellyrowland/openmc,wbinventor/openmc,mit-crpg/openmc,smharper/openmc,johnnyliu27/openmc,liangjg/openmc,mjlong/openmc,shikhar413/openmc,mit-crpg/openmc,shikhar413/openmc,paulromano/openmc,amandalund/openmc,kellyrowland/openmc,paulromano/openmc,wbinventor/openmc,mit-crpg/openmc,liangjg/openmc,smharper/openmc,walshjon/openmc,wbinventor/openmc,johnnyliu27/openmc,shikhar413/openmc,samuelshaner/openmc,walshjon/openmc,paulromano/openmc,mit-crpg/openmc,johnnyliu27/openmc,samuelshaner/openmc,amandalund/openmc,walshjon/openmc,bhermanmit/openmc,mjlong/openmc,paulromano/openmc,shikhar413/openmc,smharper/openmc,amandalund/openmc,wbinventor/openmc,liangjg/openmc,samuelshaner/openmc,bhermanmit/openmc,johnnyliu27/openmc,amandalund/openmc