code: public String getDestinationFilename(final DocWorkUnit workUnit) {
          return DocletUtils.phpFilenameForClass(workUnit.getClazz(), HelpDoclet.outputFileExtension);
      }
docs: Return the flat filename (no paths) that the handler would like the Doclet to
  write out the documentation for workUnit
  @param workUnit
  @return the name of the destination file to which documentation output will be written