The SLICC HTML generator does not work without the 'desc' property of the STATES and EVENTS found in the protocol state machine source files. This adds the 'desc' property in MESI_Three_Level to declarations where it was missing and cleans up the text of some existing ones. Issue-on: https://gem5.atlassian.net/browse/GEM5-357 Change-Id: I2d0f8e11889554063fed798e724217963d4a74de Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/24256 Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br> Reviewed-by: Jason Lowe-Power <power.jg@gmail.com> Tested-by: Gem5 Cloud Project GCB service account <345032938727@cloudbuild.gserviceaccount.com> Tested-by: kokoro <noreply+kokoro@google.com> Maintainer: Jason Lowe-Power <power.jg@gmail.com>