Fix JavaDoc in GHRepository

Author: bitwiseman

src/main/java/org/kohsuke/github/GHRepository.java

@@ -3220,6 +3220,8 @@ public <T> T readTar(InputStreamFunction<T> streamFunction, String ref) throws I
      *            the eventType
      * @param clientPayload
      *            a custom payload , can be nullable
+     * @param <T>
+     *            type of client payload
      * @throws IOException
      *             the io exception
      */