lisp/*: Add declarations, remove unused bindings, mark unused args.

lisp/*: Add declarations, remove unused bindings, mark unused args.

* lisp/avoid.el (mouse-avoidance-mode): Mark unused arg.
  (mouse-avoidance-nudge-mouse): Remove unused binding.

* lisp/imenu.el (imenu-default-goto-function): Mark unused args.
  (imenu-progress-message): Remove obsolete macro; all callers changed.

* lisp/mouse.el (mouse-menu-major-mode-map):
* lisp/emacs-lisp/authors.el (authors-scan-change-log)
  (authors-add-to-author-list):
* lisp/emacs-lisp/avl-tree.el (avl-tree--enter-balance):
* lisp/emacs-lisp/smie.el (smie-auto-fill):
* lisp/mail/sendmail.el (mail-bury):
* lisp/mail/unrmail.el (unrmail):
* lisp/net/tls.el (open-tls-stream):
* lisp/textmodes/picture.el (picture-mouse-set-point):
  Remove unused bindings.

* lisp/subr.el (keymap-canonicalize): Remove unused binding.
  (read-passwd): Mark unused arg.

* lisp/tutorial.el (tutorial--display-changes): Remove unused binding.
  (tutorial--save-tutorial-to): Remove unused variable.

* lisp/emacs-lisp/package.el (define-package, package-menu-mark-delete)
  (package-menu-mark-install, package-menu-mark-unmark): Mark unused args.
  (package-generate-autoloads, package-menu--generate)
  (package-menu--find-upgrades): Remove unused bindings.

* lisp/emulation/cua-rect.el (cua-restrict-regexp-rectangle)
  (cua-restrict-prefix-rectangle): Doc fixes.  Remove unused bindings.
  (cua--mouse-ignore, cua--delete-rectangle, cua--extract-rectangle)
  (cua--indent-rectangle, cua-open-rectangle, cua-close-rectangle)
  (cua-blank-rectangle, cua-string-rectangle, cua-replace-in-rectangle)
  (cua-incr-rectangle, cua-sequence-rectangle, cua--convert-rectangle-as)
  (cua--rectangle-aux-replace, cua--left-fill-rectangle)
  (cua-scroll-rectangle-up, cua-scroll-rectangle-down)
  (cua-delete-char-rectangle): Mark unused args.
  (cua-align-rectangle): Remove unused binding.

* lisp/mail/rmail.el (compilation--message->loc)
  (epa--find-coding-system-for-mime-charset): Declare.

* lisp/net/dbus.el (dbus-register-service): Declare.
  (dbus-name-owner-changed-handler): Remove unused binding.

* lisp/nxml/nxml-mode.el (nxml-electric-slash, nxml-in-mixed-content-p)
  (nxml-compute-indent-from-matching-start-tag): Remove unused variables.
  (nxml-scan-backward-within): Mark unused arg.
  (nxml-dynamic-markup-word): Remove unused binding.