code: public String apply(final String markup) {
          if (tags.isEmpty()) {
              return markup;
          }
  
          if (null == tagletPattern) {
              tagletPattern = Pattern.compile(createTagletPattern(), Pattern.MULTILINE);
          }
  
          final Matcher matcher = tagletPattern.matcher(markup);
          if (!matcher.find()) {
              return markup;
          }
  
          matcher.reset();
          return doApply(matcher);
      }
docs: Parse the markup and applies all {@linkplain #register(MarkdownTaglet) registered} and found {@link MarkdownTaglet}s.
  
  @param markup the (raw) markup
  @return the generated markdown