* lisp: Remove yet more always-nil variables

* lisp: Remove yet more always-nil variables

* lisp/align.el (align-region):
Remove always-nil variable `group-c`.
* lisp/ido.el (ido-make-prompt): Remove always-nil variable `prefix`.

* lisp/xdg.el (xdg-mime-collect-associations):
Remove always-nil variable `end`.

* lisp/calc/calc-yank.el (calc-edit):
Remove always-nil variable `flag`.

* lisp/calendar/todo-mode.el (todo-edit-item--header):
Remove always-nil variable `dayname`.
(todo-show-categories-table):
Remove always-nil variable `sortkey`.

* lisp/emacs-lisp/checkdoc.el (checkdoc-ispell-docstring-engine):
Remove always-nil variable `err`.

* lisp/emacs-lisp/tcover-ses.el: Remove always-nil variable `pause`.

* lisp/eshell/em-ls.el (eshell-ls-files):
Remove always-nil variable `ignore`.

* lisp/net/ange-ftp.el (ange-ftp-copy-file-internal): Remove always-nil
variable `temp2`.

* lisp/progmodes/cperl-mode.el (cperl-tags-hier-init): Remove
always-nil variables `l1`, `l2`, `l3`.
(cperl-tags-treeify): Remove always-nil variable `l1`.

* lisp/progmodes/ebrowse.el (ebrowse-tags-read-member+class-name):
Remove always-nil variable `class`.

* lisp/textmodes/artist.el (artist-draw-ellipse-with-0-height):
Remove always-nil variable `fill-info`.

* lisp/textmodes/flyspell.el (flyspell-emacs-popup):
Remove always-nil variable `show-affix-info`.

* lisp/textmodes/rst.el (rst-Ado):
Remove always-nil variable `char`.

* lisp/vc/vc.el (vc-diff-build-argument-list-internal):
Remove always-nil variable `rev2-default`.