docs: public static String delFirst(String regex, CharSequence content) {
  		if (StrUtil.hasBlank(regex, content)) {
  			return StrUtil.str(content);
  		}
  
  		// Pattern pattern = Pattern.compile(regex, Pattern.DOTALL);
  		final Pattern pattern = PatternPool.get(regex, Pattern.DOTALL);
  		return delFirst(pattern, content);
  	}