Fixed indentation for keff_trigger threshold in docs
Fixed indentation for keff_trigger threshold in docs

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