docs: public static String escape(CharSequence content) {
  		if (StrUtil.isBlank(content)) {
  			return StrUtil.str(content);
  		}
  
  		final StringBuilder builder = new StringBuilder();
  		int len = content.length();
  		char current;
  		for (int i = 0; i < len; i++) {
  			current = content.charAt(i);
  			if (RE_KEYS.contains(current)) {
  				builder.append('\\');
  			}
  			builder.append(current);
  		}
  		return builder.toString();
  	}