Also remove various redundant `:group` arguments.

* lisp/erc/erc-backend.el (define-erc-response-handler): Move `declare`
after the docstring.

* lisp/erc/erc-capab.el: Use lexical-binding.
(erc-capab-identify-activate): Simplify with `member`.

* lisp/erc/erc-dcc.el (erc-dcc): Move before erc-dcc-mode definition,
which refers to it.
(erc-dcc-chat-accept): Remove unused vars `nick` and `buffer`.

* lisp/erc/erc-imenu.el: Use lexical-binding.
(erc-create-imenu-index): Remove unused var `prev-pos`.

* lisp/erc/erc-match.el: Use lexical-binding.
(erc-match-message): Remove unused var `old-pt`.
(erc-match-message): Strength-reduce `eval` to `symbol-value`.

* lisp/erc/erc-page.el: Use lexical-binding.
(erc-page): Move Custom group before `erg-page-mode` which refers to it.

* lisp/erc/erc-replace.el: Use lexical-binding.
(erc-replace-insert): Use `functionp`.

* lisp/erc/erc-status-sidebar.el: Use lexical-binding.
(erc-status-sidebar-open): Remove unused var `sidebar-window`.

* lisp/erc/erc.el: Fix header to use the customary 3 semi-colons.
(erc-fill-column): Declare variable.

* lisp/erc/erc-autoaway.el: Use lexical-binding.
* lisp/erc/erc-ezbounce.el: Use lexical-binding.
* lisp/erc/erc-fill.el: Use lexical-binding.
* lisp/erc/erc-goodies.el: Use lexical-binding.
* lisp/erc/erc-ibuffer.el: Use lexical-binding.
* lisp/erc/erc-identd.el: Use lexical-binding.
* lisp/erc/erc-join.el: Use lexical-binding.
* lisp/erc/erc-lang.el: Use lexical-binding.
* lisp/erc/erc-log.el: Use lexical-binding.
* lisp/erc/erc-menu.el: Use lexical-binding.
* lisp/erc/erc-netsplit.el: Use lexical-binding.
* lisp/erc/erc-networks.el: Use lexical-binding.
* lisp/erc/erc-pcomplete.el: Use lexical-binding.
* lisp/erc/erc-ring.el: Use lexical-binding.
* lisp/erc/erc-speedbar.el: Use lexical-binding.
* lisp/erc/erc-spelling.el: Use lexical-binding.
* lisp/erc/erc-truncate.el: Use lexical-binding.
* lisp/erc/erc-xdcc.el: Use lexical-binding.

* lisp/erc/erc-backend.el:
* lisp/erc/erc-button.el:
* lisp/erc/erc-dcc.el:
* lisp/erc/erc-identd.el:
* lisp/erc/erc-join.el:
* lisp/erc/erc-lang.el:
* lisp/erc/erc-log.el:
* lisp/erc/erc-match.el:
* lisp/erc/erc-menu.el:
* lisp/erc/erc-pcomplete.el:
* lisp/erc/erc-replace.el:
* lisp/erc/erc-spelling.el:
* lisp/erc/erc-stamp.el:
* lisp/erc/erc-track.el:
* lisp/erc/erc-xdcc.el: Remove irrelevant entries in Keywords header.

Run "TZ=UTC0 admin/update-copyright".

* lisp/erc/erc-autoaway.el, lisp/erc/erc-button.el,
lisp/erc/erc-compat.el, lisp/erc/erc-fill.el, lisp/erc/erc-imenu.el,
lisp/erc/erc-join.el, lisp/erc/erc-lang.el, lisp/erc/erc-match.el,
lisp/erc/erc-pcomplete.el, lisp/erc/erc-ring.el,
lisp/erc/erc-spelling.el, lisp/erc/erc-stamp.el,
lisp/erc/erc-track.el: Update URL to friendlier form, over https.
* lisp/erc/erc-ibuffer.el: Remove URL to nonexistent page.
* lisp/erc/erc-list.el, lisp/erc/erc-log.el, lisp/erc/erc-notify.el,
lisp/erc/erc-replace.el, lisp/erc/erc-services.el,
lisp/erc/erc-sound.el, lisp/erc/erc-speedbar.el,
lisp/erc/erc-truncate.el: Add URL to corresponding EmacsWiki page.

* admin/MAINTAINERS: Add entries for Amin Bandali, new maintainer for
ERC, and interested in maintaining Eshell.
* lisp/erc/*: New maintainer.

Run "TZ=UTC0 admin/update-copyright $(git ls-files)".

Restore lines saying "Maintainer: emacs-devel@gnu.org" when there is
no special maintainer for a file.  Although this wasn't documented
it was common practice and removing the lines didn't have consensus.

Mostly, this just removes "Maintainer: emacs-devel@gnu.org" lines,
which are not that useful.  It also cleans up and regularizes a
few similar lines.