fix(history): address PR #116 review feedback

- console: drop orphaned `/logging chat` reference from
  cons_privacy_setting() — the subcommand was removed, PREF_CHLOG now
  tracks PREF_HISTORY implicitly
- console: delete cons_logging_setting() and remove its call from
  cons_show_log_prefs() — every line in it referenced /logging chat or
  /logging group, both now invalid after the deprecation below
- command: deprecate /logging command. It now prints a single notice
  pointing to /history; CMD_PREAMBLE trimmed (min_args=0, no
  setting_func, syntax/args/examples dropped); subcommand 'group'
  removed from autocomplete

The SQLite history-load gap for /correction off is split out into a
follow-up — out of scope for this PR.

src/ui/console.c

@@ -1948,27 +1948,12 @@ cons_log_setting(void)
     cons_show("Log level (/log level)      : %s", level);
 }
 
-void
-cons_logging_setting(void)
-{
-    if (prefs_get_boolean(PREF_CHLOG))
-        cons_show("Chat logging (/logging chat)                : ON");
-    else
-        cons_show("Chat logging (/logging chat)                : OFF");
-
-    if (prefs_get_boolean(PREF_GRLOG))
-        cons_show("Groupchat logging (/logging group)          : ON");
-    else
-        cons_show("Groupchat logging (/logging group)          : OFF");
-}
-
 void
 cons_show_log_prefs(void)
 {
     cons_show("Logging preferences:");
     cons_show("");
     cons_log_setting();
-    cons_logging_setting();
 
     cons_alert(NULL);
 }
@@ -2862,11 +2847,6 @@ cons_privacy_setting(void)
 {
     cons_show("Database logging                                           : %s", prefs_get_string(PREF_DBLOG));
 
-    if (prefs_get_boolean(PREF_CHLOG)) {
-        cons_show("Chat logging (/logging chat)                               : ON");
-    } else {
-        cons_show("Chat logging (/logging chat)                               : OFF");
-    }
     if (prefs_get_boolean(PREF_HISTORY)) {
         cons_show("Chat history (/history)                                    : ON");
     } else {

src/ui/ui.h

@@ -330,7 +330,6 @@ void cons_history_setting(void);
 void cons_carbons_setting(void);
 void cons_receipts_setting(void);
 void cons_log_setting(void);
-void cons_logging_setting(void);
 void cons_autoaway_setting(void);
 void cons_reconnect_setting(void);
 void cons_autoping_setting(void);