constructor() {
        this.matchIndexes = {};
        // @ts-ignore
        this.regexes = [];
        this.matchAt = 1;
        this.position = 0;
      }
Stores multiple regular expressions and allows you to quickly search for
      them all in a string simultaneously - returning the first match.  It does
      this by creating a huge (a|b|c) regex - each individual item wrapped with ()
      and joined by `|` - using match groups to track position.  When a match is
      found checking which position in the array has content allows us to figure
      out which of the original regexes / match groups triggered the match.

      The match object itself (the result of `Regex.exec`) is returned but also
      enhanced by merging in any meta-data that was registered with the regex.
      This is how we keep track of which mode matched, and what type of rule
      (`illegal`, `begin`, end, etc).