/"/ and /'/ marks the rest of file (until another quote character) to be
highlighted as string literal.
General delimeted input like %r!watever! or %q[abc] are not supported either.
Some broken examples:
1
/'/ =~ '"' 2
/"/ 3
/"/ 4
/"/ 5
'"' 6
# comment extends from ' in 2 until " in 3, similarly from 4 to 5
%r[hello]
%r!hello!
%r'hello'
%w[ a b c d 1 ]
'this is a string'
%q/this is a string/
# nothing above is supported