Make controls in menu() optional (#5678)

* Make `controls` in `menu()` optional

You might wonder, shouldn't we pass `None` to functions from controls?
No, we shouldn't because when `None` is passed, only DEFAULT_CONTROLS
can be used and that means that the length of pages list won't change.

* Update usage in core and core cogs

* Add missing docstrings to `redbot.core.utils.menus` module

redbot/core/core_commands.py

@@ -18,7 +18,7 @@ import pip
 import traceback
 from pathlib import Path
 from redbot.core import data_manager
-from redbot.core.utils.menus import menu, DEFAULT_CONTROLS
+from redbot.core.utils.menus import menu
 from redbot.core.commands import GuildConverter, RawUserIdConverter
 from string import ascii_letters, digits
 from typing import TYPE_CHECKING, Union, Tuple, List, Optional, Iterable, Sequence, Dict, Set
@@ -1659,7 +1659,7 @@ class Core(commands.commands._RuleDropper, commands.Cog, CoreLogic):
         if len(pages) == 1:
             await ctx.send(pages[0])
         else:
-            await menu(ctx, pages, DEFAULT_CONTROLS)
+            await menu(ctx, pages)
 
     @commands.command(require_var_positional=True)
     @checks.is_owner()