More context in Bug#80786 and:
https://lists.gnu.org/archive/html/emacs-orgmode/2026-03/msg00286.html
`icalendar-recur' as a type name for RRULE values was confusing and made
the accessors for this type difficult to discover, because `icalendar-recur-'
is also used as a prefix in icalendar-recur.el. This change renames the
`icalendar-recur' type to `icalendar-rrule-value' and renames the
accessor functions for these values appropriately.
* lisp/calendar/icalendar-parser.el: Rename symbols as follows:
(icalendar-recur): `icalendar-rrule-value'
(icalendar-read-recur-rule-part): `icalendar-read-rrule-part'
(icalendar-print-recur-rule-part): `icalendar-print-rrule-part'
(icalendar-recur-rule-part): `icalendar-rrule-part'
(icalendar-read-recur): `icalendar-read-rrule-value'
(icalendar-print-recur): `icalendar-print-rrule-value'
(icalendar--recur-value-types): `icalendar--rrule-value-types'
(icalendar-recur-value-p): `icalendar-rrule-value-p'
(icalendar-recur-freq): `icalendar-rrule-freq'
(icalendar-recur-interval-size): `icalendar-rrule-interval-size'
(icalendar-recur-until): `icalendar-rrule-until'
(icalendar-recur-count): `icalendar-rrule-count'
(icalendar-recur-weekstart): `icalendar-rrule-weekstart'
(icalendar-recur-by*): `icalendar-rrule-by*'.
(icalendar-rrule):
(icalendar-index-insert):
(icalendar-index-get): Update references.
* lisp/calendar/icalendar-recur.el (icalendar-recur-find-interval):
(icalendar-recur-nth-interval):
(icalendar-recur-next-interval):
(icalendar-recur-previous-interval):
(icalendar-recur-refine-from-clauses):
(icalendar-recur-recurrences-in-interval):
(icalendar-recur-recurrences-in-window):
(icalendar-recur-recurrences-to-count):
(icalendar-recur-tz-observance-on): Update references.
* lisp/calendar/diary-icalendar.el: Update references.
* lisp/calendar/icalendar-shortdoc.el (icalendar): Update shortdoc examples.
* lisp/gnus/gnus-icalendar.el: Update references.
* test/lisp/calendar/diary-icalendar-tests.el:
* test/lisp/calendar/icalendar-parser-tests.el:
* test/lisp/calendar/icalendar-recur-tests.el: Update references in tests.