message: Remove obsolete comment about loglevels
  The nonstandard loglevel equivalents have been removed, but I forgot
  to update this comment.
  Cr-Commit-Position: refs/heads/main@{#36158}
diff: namespace rtc {
  //////////////////////////////////////////////////////////////////////
  -
  -// Note that the non-standard LoggingSeverity aliases exist because they are
  -// still in broad use. The meanings of the levels are:
  +// The meanings of the levels are:
  // LS_VERBOSE: This level is for data which we do not want to appear in the
  // normal debug log, but should appear in diagnostic logs.
  // LS_INFO: Chatty level used in debugging for all sorts of things, the default
  