R error pattern #6 was wrongly highlighted

git-svn-id: https://svn.r-project.org/ESS/trunk@5747 0bbaf3bd-34e0-0310-bf65-c717079852d4
don't pin error and warning messages to bol

git-svn-id: https://svn.r-project.org/ESS/trunk@5748 0bbaf3bd-34e0-0310-bf65-c717079852d4