* lisp/gnus/gnus-icalendar.el
(gnus-icalendar-event--build-reply-event-body): Add optional COMMENT
argument to be inserted into the reply.
(gnus-icalendar-event-reply-from-buffer): Add COMMENT argument to be
passed through to gnus-icalendar-event--build-reply-event-body
(gnus-icalendar-reply-accept, gnus-icalendar-reply-tentative,
gnus-icalendar-reply-decline): If interactively called with a prefix
argument ask user for a COMMENT to add to the reply.
* test/lisp/gnus/gnus-icalendar-tests.el
(gnus-icalendar-accept-with-comment,
gnus-icalendar-decline-without-changing-comment): New tests.
* lisp/gnus/gnus-icalendar.el (gnus-icalendar-event--get-attendee-names)
(gnus-icalendar-event-from-ical): Do not default to REQ-PARTICIPANT
if the user was not found as an attendee.
* test/lisp/gnus/gnus-icalendar-tests.el
(gnus-icalendary-weekly-byday): Remove the ROLE property to test
that it correctly defaults to REQ-PARTICIPANT. The case where the
user is not listed is covered by gnus-icalendar-parse already
(bug#50749).
* lisp/gnus/gnus-icalendar.el
(gnus-icalendar-event:recurring-interval): Fix parsing of weekly
recurring events (bug#43669).
Example: in the absence of explicit INTERVAL value in the calendar
event, a weekly event with occurrences scheduled for Mondays and
Wednesdays should receive the default recurring interval of "1" and the
org mode timestamp repeater should be "+1w".
Due to a bug in the current code we receive "WEEKLY" and "+WEEKLYw"
instead. The patch fixes the issue.
* test/lisp/gnus/gnus-icalendar-tests.el:
(icalendar-tests--get-ical-event): Remove unused function accidentally
copy-pasted from icalendar-tests.el.
(gnus-icalendar-parse, gnus-icalendary-byday):
Remove unintended initial newlines.
Duplicate comma-escaping backslashes so that they have intended
effects, conforming to RFC 5545.
Remove ineffective comma-escaping backslashes where not intended.
* lisp/gnus/gnus-icalendar.el
(gnus-icalendar-event:recurring-days): New function (bug#39782).
(gnus-icalendar-event:org-timestamp): New function.
(gnus-icalendar--find-day): Use them.
(gnus-icalendar-event--org-timestamp): Ditto.
