Although they are now supported by the lexer
and parser, it is worth to remind that we still
need to address an issue concerning the highlight
of multiline literals (which with the advent of
the new raw strings will become more common).

Task-number: QTCREATORBUG-6722
Change-Id: I137337a9ac0152a1f8b9faded0b960c6fe3dd38a
Reviewed-by: Roberto Raggi <roberto.raggi@nokia.com>