Update missing label in documentation
Update missing label in documentation

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