vendors/tempy.js/createRule
    var createRule = (pattern, ignoreCase) => {
      const origin = pattern;
      let negative = false;
      if (pattern.indexOf("!") === 0) {
        negative = true;
        pattern = pattern.substr(1);
      }
      pattern = pattern.replace(REGEX_REPLACE_LEADING_EXCAPED_EXCLAMATION, "!").replace(REGEX_REPLACE_LEADING_EXCAPED_HASH, "#");
      const regex = makeRegex(pattern, ignoreCase);
      return new IgnoreRule(origin, pattern, negative, regex);
    };