code: func (l *lexer) acceptRunUntil(until rune) bool {
  	// Continues running until a rune is found
  	for i := l.next(); !strings.ContainsRune(string(until), i); i = l.next() {
  		if i == 0 {
  			return false
  		}
  	}
  
  	return true
  }
docs: // acceptRunUntil is the inverse of acceptRun and will continue
  // to advance the seeker until the rune has been found.