Add mini modules bufbar and nickbar to ERC

* doc/misc/erc.texi: Add `bufbar' and `nickbar' to known modules.
Also add `keep-place', which was missing, and remove `bbdb', which is
not part of ERC.  Add new section "Auxiliary Modules" for listing
experimental modules or those typically managed by some other feature.
* erc/ERC-NEWS: Mention new mini modules for libraries
erc-status-sidebar.el and erc-speedbar.el.
* lisp/erc/erc.el (erc-modules): Add `bufbar' and `nickbar' to
selection of offered modules.
* test/lisp/erc/erc-tests.el (erc-tests--modules): Add `bufbar' and
`nickbar'.  (Bug#63595)

doc/misc/erc.texi

@@ -414,9 +414,10 @@ Set away status automatically
 @item autojoin
 Join channels automatically
 
-@cindex modules, bbdb
-@item bbdb
-Integrate with the Big Brother Database
+@cindex modules, bufbar
+@item bufbar
+List buffers belonging to a connection in a side window; part of
+Custom group @code{erc-status-sidebar}
 
 @cindex modules, button
 @item button
@@ -443,6 +444,10 @@ Launch an identd server on port 8113
 @item irccontrols
 Highlight or remove IRC control characters
 
+@cindex modules, keep-place
+@item keep-place
+Remember your position in buffers
+
 @cindex modules, log
 @item log
 Save buffers in logs
@@ -463,6 +468,11 @@ Detect netsplits
 @item nicks
 Automatically colorize nicks
 
+@cindex modules, nickbar
+@item nickbar
+List participating nicks for the current target buffer in a side
+window; part of Custom group @code{erc-speedbar}
+
 @cindex modules, noncommands
 @item noncommands
 Don't display non-IRC commands after evaluation
@@ -534,6 +544,33 @@ Translate morse code in messages
 
 @end table
 
+@anchor{Auxiliary Modules}
+@subheading Auxiliary Modules
+@cindex auxiliary modules
+
+For various reasons, the following modules aren't currently listed in
+the Custom interface for @code{erc-modules}, but feel free to add them
+explicitly.  They may be managed by another module or considered more
+useful when toggled interactively or just deemed experimental.
+
+@table @code
+
+@cindex modules, fill-wrap
+@item fill-wrap
+Wrap long lines using @code{visual-line-mode}
+
+@cindex modules, keep-place-indicator
+@item keep-place-indicator
+Remember your place in buffers with a visible reminder; activated
+interactively or via something like @code{erc-join-hook}
+
+@cindex modules, services-regain
+@item services-regain
+Automatically ask NickServ to reclaim your nick when reconnecting;
+experimental as of ERC 5.6
+
+@end table
+
 @anchor{Required Modules}
 @subheading Required Modules
 @cindex required modules

etc/ERC-NEWS

@@ -84,6 +84,22 @@ widget has been an age-old annoyance for new users.  Previously
 ineffective, this method now actually works, but it also admonishes
 users to edit the 'erc-modules' widget instead.
 
+** ERC's status-sidebar has gained an accompanying module.
+Users can now add 'bufbar' to 'erc-modules' to achieve the same effect
+as toggling 'erc-status-sidebar-open' manually at the start of an IRC
+session.  The module has also been outfitted to show channels and
+queries under their respective servers by default.  To avoid
+confusion, the major mode used for the sidebar buffer itself,
+'erc-status-sidebar-mode', is no longer available interactively.
+
+** A new spin on a classic integration in erc-speedbar.
+Add 'nickbar' to 'erc-modules' to spawn a dynamically updating side
+window listing all the users in any target buffer.  It's powered by
+the same speedbar.el integration you've always known, except this
+one's optionally accessible from the keyboard, just like any other
+side window.  Hit '<RET>' over a nick to spawn a "/QUERY" or a
+"Lastlog" (Occur) session.  See 'erc-nickbar-mode' for more.
+
 ** The option 'erc-timestamp-use-align-to' is more versatile.
 While this option has always offered to right-align stamps via the
 'display' text property, it's now more effective at doing so when set

lisp/erc/erc.el

@@ -2046,6 +2046,7 @@ removed from the list will be disabled."
     :greedy t
     (const :tag "autoaway: Set away status automatically" autoaway)
     (const :tag "autojoin: Join channels automatically" autojoin)
+    (const :tag "bufbar: Show ERC buffers in a side window" bufbar)
     (const :tag "button: Buttonize URLs, nicknames, and other text" button)
     (const :tag "capab: Mark unidentified users on servers supporting CAPAB"
            capab-identify)
@@ -2066,6 +2067,7 @@ removed from the list will be disabled."
            move-to-prompt)
     (const :tag "netsplit: Detect netsplits" netsplit)
     (const :tag "networks: Provide data about IRC networks" networks)
+    (const :tag "nickbar: Show nicknames in a dyamic side window" nickbar)
     (const :tag "nicks: Uniquely colorize nicknames in target buffers" nicks)
     (const :tag "noncommands: Don't display non-IRC commands after evaluation"
            noncommands)

test/lisp/erc/erc-tests.el

@@ -1951,9 +1951,9 @@
     (kill-buffer "#chan")))
 
 (defconst erc-tests--modules
-  '( autoaway autojoin button capab-identify completion dcc fill identd
+  '( autoaway autojoin bufbar button capab-identify completion dcc fill identd
      imenu irccontrols keep-place list log match menu move-to-prompt netsplit
-     networks nicks noncommands notifications notify page readonly
+     networks nickbar nicks noncommands notifications notify page readonly
      replace ring sasl scrolltobottom services smiley sound
      spelling stamp track truncate unmorse xdcc))