code: public static String buildHelpPageUrl(String helpPage) {
          try {
              if (helpPage.matches("[hH][tT][tT][pP][sS]?://.*")) {
                  log.debug("Help page URL found, skipping building link to "+WIKI_BASE);
                  return helpPage;
              }
          } catch (PatternSyntaxException ex) {
              log.warn("Invalid regex", ex);
          }
  
          if (helpPage.endsWith("Gui")) {
              helpPage = helpPage.substring(0, helpPage.length() - 3);
          }
          return WIKI_BASE + helpPage + "/?utm_source=jmeter&utm_medium=helplink&utm_campaign=" + helpPage;
      }
docs: Builds full URL from wiki page name unless a URL is already passed in.
  
  @param helpPage wiki page name (not full URL) or URL to external wiki
  @return full URL to helpPage