lisp/erc: Use lexical-binding

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-ezbounce.el

@@ -1,4 +1,4 @@
-;;; erc-ezbounce.el ---  Handle EZBounce bouncer commands
+;;; erc-ezbounce.el ---  Handle EZBounce bouncer commands  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2002, 2004, 2006-2021 Free Software Foundation, Inc.
 
@@ -33,7 +33,6 @@
 
 (defcustom erc-ezb-regexp "^ezbounce!srv$"
   "Regexp used by the EZBouncer to identify itself to the user."
-  :group 'erc-ezbounce
   :type 'regexp)
 
 (defcustom erc-ezb-login-alist '()
@@ -44,7 +43,6 @@ The alist's format is as follows:
  (((server . port) . (username . password))
   ((server . port) . (username . password))
   ...)"
-  :group 'erc-ezbounce
   :type '(repeat
 	  (cons (cons :tag "Server"
 		     string
@@ -68,7 +66,7 @@ The alist's format is as follows:
   "Indicate whether current notices are expected to be EZB session listings.")
 
 ;;;###autoload
-(defun erc-cmd-ezb (line &optional force)
+(defun erc-cmd-ezb (line &optional _force)
   "Send EZB commands to the EZBouncer verbatim."
   (erc-server-send (concat "EZB " line)))
 (put 'erc-cmd-EZB 'do-not-parse-args t)
@@ -102,7 +100,7 @@ in the alist is nil, prompt for the appropriate values."
     found))
 
 ;;;###autoload
-(defun erc-ezb-notice-autodetect (proc parsed)
+(defun erc-ezb-notice-autodetect (_proc parsed)
   "React on an EZBounce NOTICE request."
   (let* ((sender (erc-response.sender parsed))
 	 (message (erc-response.contents parsed))
@@ -113,7 +111,7 @@ in the alist is nil, prompt for the appropriate values."
   nil)
 
 ;;;###autoload
-(defun erc-ezb-identify (message)
+(defun erc-ezb-identify (_message)
   "Identify to the EZBouncer server."
   (let ((login (erc-ezb-get-login erc-session-server (erc-port-to-string erc-session-port))))
     (unless (null login)
@@ -122,13 +120,13 @@ in the alist is nil, prompt for the appropriate values."
 	(erc-server-send (concat "LOGIN " username " " pass))))))
 
 ;;;###autoload
-(defun erc-ezb-init-session-list (message)
+(defun erc-ezb-init-session-list (_message)
   "Reset the EZBounce session list to nil."
   (setq erc-ezb-session-list nil)
   (setq erc-ezb-inside-session-listing t))
 
 ;;;###autoload
-(defun erc-ezb-end-of-session-list (message)
+(defun erc-ezb-end-of-session-list (_message)
   "Indicate the end of the EZBounce session listing."
   (setq erc-ezb-inside-session-listing nil))
 
@@ -143,7 +141,7 @@ in the alist is nil, prompt for the appropriate values."
       (add-to-list 'erc-ezb-session-list (list id nick to)))))
 
 ;;;###autoload
-(defun erc-ezb-select (message)
+(defun erc-ezb-select (_message)
   "Select an IRC server to use by EZBounce, in ERC style."
   (unless (and erc-ezb-session-list
 	       (erc-ezb-select-session))
@@ -169,7 +167,7 @@ in the alist is nil, prompt for the appropriate values."
 ;;;###autoload
 (defun erc-ezb-initialize ()
   "Add EZBouncer convenience functions to ERC."
-  (add-hook 'erc-server-NOTICE-functions 'erc-ezb-notice-autodetect))
+  (add-hook 'erc-server-NOTICE-functions #'erc-ezb-notice-autodetect))
 
 (provide 'erc-ezbounce)