This change updates gnus-icalendar.el to use the new iCalendar
library instead of obsolete functions from icalendar.el.
* lisp/gnus/gnus-icalendar.el
(gnus-icalendar-event)
(gnus-icalendar-event:recurring-p)
(gnus-icalendar-event:recurring-interval)
(gnus-icalendar-event:recurring-days)
(gnus-icalendar-event--find-attendee)
(gnus-icalendar-event-from-ical)
(gnus-icalendar-event-from-buffer)
(gnus-icalendar-event--build-reply)
(gnus-icalendar-event-reply-from-buffer)
(gnus-icalendar-event:org-repeat): Reimplement using new iCalendar functions.
(gnus-icalendar-event--attendees-by-type): Rename from
`gnus-icalendar-event--get-attendee-names'.
(gnus-icalendar-event--build-reply): Rename from
`gnus-icalendar-event--build-reply-event-body'.
(gnus-icalendar--format-participant-list): Expect list of
`icalendar-attendee's.  Add docstring.
(Bug#80426)

* test/lisp/gnus/gnus-icalendar-tests.el: Update tests.

* lisp/gnus/gnus-delay.el (gnus-delay-article): Accept YYYY-MM-DD
hh:mm(:ss) as a valid format.  (Bug#80637)

Copyright-paperwork-exempt: yes

* lisp/gnus/message.el (message-put-addresses-in-ecomplete):
Handle "BCC" and "X-Debbugs-CC" headers.

* etc/NEWS: Fix capitalization and markup.
* lisp/emacs-lisp/ert.el (ert--should-error-handle-error): Prefer
any over cl-some where either will do.
* lisp/epa-file.el (epa-file--find-file-not-found-function):
Reindent.
(epa-file--error-add-context): Use correct variables.  Add
docstring.
* lisp/ffap.el (ffap-machine-p):
* lisp/gnus/nnmaildir.el (nnmaildir--emlink-p): Prefer
string-equal-ignore-case over case fiddling.
* lisp/gnus/gnus-search.el (gnus-search-run-query): Fix typo in
error re-signaling.
* lisp/ibuffer.el (ibuffer-confirm-operation-on): Prefer string
search over regexp matching where either will do.
* test/lisp/vc/vc-tests/vc-tests.el
(vc-test--run-maybe-unsupported-function): Pacify unused
condition-case error variable warnings (bug#72212).

* lisp/vc/smerge-mode.el (smerge-extend):
* lisp/vc/diff-mode.el (diff-beginning-of-file-and-junk):
* lisp/transient.el (transient--with-emergency-exit):
* lisp/textmodes/tex-mode.el (latex-forward-sexp):
* lisp/tar-mode.el (tar-mode):
* lisp/savehist.el (savehist--reload):
* lisp/progmodes/octave.el (inferior-octave-resync-dirs):
* lisp/progmodes/js.el (js--re-search-forward):
* lisp/plstore.el (plstore--decrypt):
* lisp/net/dbus.el (dbus-ignore-errors, dbus-register-signal)
(dbus-handle-event):
* lisp/mouse.el (mouse-drag-track, mouse-drag-region-rectangle):
* lisp/minibuffer.el (completion-pcm--find-all-completions):
* lisp/mail/rfc2231.el (rfc2231-parse-string):
* lisp/mail/rfc2047.el (rfc2047-encode-region):
* lisp/jit-lock.el (jit-lock-fontify-now):
* lisp/international/ja-dic-utl.el (skkdic-lookup-key):
* lisp/gnus/nnselect.el (nnselect-generate-artlist):
* lisp/gnus/mml-sec.el (mml-secure-epg-encrypt, mml-secure-epg-sign):
* lisp/gnus/mail-source.el (mail-source-fetch-pop)
(mail-source-check-pop):
* lisp/gnus/gnus-art.el (gnus-article-read-summary-keys):
* lisp/files.el (basic-save-buffer-2, files--ensure-directory)
(files--force, copy-directory):
* lisp/eshell/esh-io.el (eshell-output-object-to-target):
* lisp/epa.el (epa-decrypt-file, epa-verify-file, epa-sign-file)
(epa-encrypt-file, epa-decrypt-region, epa-verify-region)
(epa-sign-region, epa-encrypt-region, epa-delete-keys)
(epa-export-keys, epa-insert-keys):
* lisp/emacs-lisp/package.el (package--unless-error):
* lisp/emacs-lisp/multisession.el (multisession--read-file-value):
* lisp/emacs-lisp/lisp.el (up-list-default-function):
* lisp/desktop.el (desktop-kill):
* lisp/calendar/time-date.el (date-to-time):
* lisp/calendar/appt.el (appt-display-message):
* lisp/calc/calc.el (calc-do):
* lisp/bookmark.el (bookmark-handle-bookmark):
* src/fileio.c (report_file_errno):
* lisp/vc/vc.el (vc-checkout, vc-pull): Use `(signal err)` instead
of `(signal (car err) (cdr err))`.

* lisp/epa-file.el (epa-file--find-file-not-found-function):
Use `error-slot-value` and `error-data`.
(epa-file-insert-file-contents): Use `error-has-type-p`,
`error-slot-value`, and `error-data`.

* lisp/jka-compr.el (jka-compr-insert-file-contents):
Use `error-has-type-p` and `error-slot-value` as well as new
re-signaling form of `signal`.

* lisp/simple.el (minibuffer-error-function): Use `error-has-type-p`.

* lisp/startup.el (startup--load-user-init-file):
Use `error-message-string`.
(command-line): Use `error-has-type-p` and `error-message-string`.

* lisp/type-break.el (type-break-demo-life):
Use `error-message-string`.

* lisp/emacs-lisp/bytecomp.el (batch-byte-compile-file):
Use `error-message-string` and `error-has-type-p`.

* lisp/emacs-lisp/edebug.el (edebug-safe-eval, edebug-report-error)
(edebug-eval-expression):
* lisp/emacs-lisp/debug.el (debugger-eval-expression):
Use `error-message-string`.

* lisp/emacs-lisp/ert.el (ert--should-error-handle-error):
Use `error-has-type-p` and `error-type`.

* lisp/net/sasl.el (sasl-error): Use `define-error`.

* lisp/net/tramp-compat.el (tramp-error-type-p): New function.
(tramp-permission-denied, tramp-compat-permission-denied): Use it.

* lisp/progmodes/elisp-mode.el (elisp-completion-at-point):
Use `error-type-p`.

* lisp/xt-mouse.el (turn-on-xterm-mouse-tracking-on-terminal)
(turn-off-xterm-mouse-tracking-on-terminal): Use `error-slot-value`.

* lisp/simple.el (next-line, previous-line): Remove useless
`condition-case` handler, and hence the whole `condition-case`, and
then simplify.

* lisp/gnus/nnrss.el (nnrss-insert): Use `with-demoted-errors`.

* lisp/gnus/nnmaildir.el (nnmaildir--emlink-p, nnmaildir--enoent-p)
(nnmaildir--eexist-p): Use `error-has-type-p`.
(nnmaildir--new-number, nnmaildir-request-set-mark): Use single-arg
`signal`.

* lisp/ffap.el (ffap-machine-p): Use `error-slot-value`.

* lisp/emacs-lisp/comp.el (comp--native-compile):
Use `error-has-type-p` as well as single-arg `signal`.

* lisp/net/ange-ftp.el (ange-ftp-hook-function): Use single-arg
`signal`.

* lisp/ebuff-menu.el (electric-buffer-menu-looper): Use `error-has-type-p`.
* lisp/progmodes/ebrowse.el (ebrowse-electric-list-looper):
Use `error-has-type-p`.
(ebrowse-electric-position-looper): Make it an alias of
`ebrowse-electric-list-looper`.

* lisp/ibuffer.el (ibuffer-confirm-operation-on):
* lisp/ls-lisp.el (ls-lisp--insert-directory):
* lisp/gnus/gnus-search.el (gnus-search-run-query):
* lisp/mail/mail-extr.el (mail-extr-safe-move-sexp):
* lisp/net/dbus.el (dbus-set-property):
* lisp/net/eudc-export.el (eudc-bbdbify-phone):
* lisp/net/imap.el (imap-fetch-safe):
* lisp/vc/vc.el (vc-root-dir): Use `error-slot-value` and
single-arg `signal` to re-signal.

* lisp/simple.el (next-line, previous-line): Remove useless
`condition-case` handler, and hence the whole `condition-case`, and
then simplify.

* lisp/emacs-lisp/comp.el (comp--error-add-context): New function.
(comp--native-compile): Use it.

* lisp/gnus/nnrss.el (nnrss-insert): Use `with-demoted-errors`.

* lisp/gnus/gnus-agent.el (gnus-agent-get-undownloaded-list):
* lisp/gnus/gnus-cloud.el (gnus-cloud-prune-old-chunks):
* lisp/gnus/gnus-draft.el (gnus-draft-check-draft-articles):
* lisp/gnus/gnus-group.el (gnus-group-sort-flat)
(gnus-group-expire-all-groups):
* lisp/gnus/gnus-sum.el (gnus-thread-highest-number):
* lisp/gnus/gnus-topic.el (gnus-topic-init-alist)
(gnus-topic-sort-topic): Replace the (lambda (x) (fun x))
pattern with #'fun.  (Bug#80382)