Slightly simplify sorted list of energies for union grid construction
Slightly simplify sorted list of energies for union grid construction

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