- fixes case where a regex would not be detected if it was anything
  other than the first parameter of a function call
- in some cases this could actually cause the whole snippet to
  be flagged as illegal if the regex contained characters that
  were invalid at the top level (such as #)

This complexity is because we only detect regexs inside "value
containers" to prevent false positivies.

This issue was found when asking Highlight.js to highlight it's
own non-minified 1.2mb browser build.