Correctly identify group work items in announce_to_lists.txt. Fixes ietf-tools#1901.

Commit ready for merge.
 - Legacy-Id: 10765

Author: larseggert

ietf/templates/submit/announce_to_lists.txt

@@ -1,6 +1,6 @@
 {% autoescape off %}
 A New Internet-Draft is available from the on-line Internet-Drafts directories.
-{% if submission.group %} This draft is a work item of the {{ submission.group.name }} Working Group of the IETF.{% endif %}
+{% if submission.group %}This draft is a work item of the {{ submission.group.name }}{% if group.type.name %} {{ group.type.name }}{% endif %} of the {% if group.type_id == "rg" %}IRTF{% else %}IETF{% endif %}.{% endif %}
 
         Title           : {{ submission.title }}
         Author{{ submission.authors_parsed|pluralize:" ,s" }}         : {% for author in submission.authors_parsed %}{{ author.name }}{% if not forloop.last %}