Add autoescape and strip tags from optional message, fixes ietf-tools#799, also

fixup formatting slightly.
 - Legacy-Id: 4081

Author: OleLaursen

ietf/templates/submit/announce_new_version.txt

@@ -1,8 +1,10 @@
-New version (-{{ submission.revision }}) has been submitted for {{ submission.filename }}-{{ submission.revision }}.txt.
+{% autoescape off %}New version (-{{ submission.revision }}) has been submitted for {{ submission.filename }}-{{ submission.revision }}.txt:
 http://www.ietf.org/internet-drafts/{{ submission.filename }}-{{ submission.revision }}.txt
-{{ msg }}
-
+{% if msg %}
+{{ msg|striptags }}
+{% endif %}
 Diff from previous version:
 http://tools.ietf.org/rfcdiff?url2={{ submission.filename }}-{{ submission.revision }}
 
 IETF Secretariat.
+{% endautoescape %}