Reverted changes to MGXS Part II notebook per suggestion by @nelsonag
Reverted changes to MGXS Part II notebook per suggestion by @nelsonag

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