Add occupants header char

`/occupants header char` now sets a character that is displayed before
the role (moderator, visitor..) in a room. Similar to `/roster header
char` is displaying a char for the roster.

Regards https://github.com/boothj5/profanity/issues/690

src/ui/console.c

@@ -1237,6 +1237,12 @@ cons_occupants_setting(void)
 
     int size = prefs_get_occupants_size();
     cons_show("Occupants size (/occupants)         : %d", size);
+
+    char header_ch = prefs_get_occupants_header_char();
+    if (header_ch)
+        cons_show("Occupants header char (/occupants)  : %c", header_ch);
+    else
+        cons_show("Occupants header char (/occupants)  : none");
 }
 
 void