chore: Sticker: fix docs and general cleanup

[Bilal2453]

Just a bit of documentation fix.

I noticed this

--[=[@p stickers ArrayIterable An iterable array of all stickers that are sent in this message.]=]
function get.stickers(self)
	if not self._stickers then
		local client = self.client
		self._stickers = ArrayIterable(self._sticker_items, function(sticker)
			if sticker.format_type == 1 then
				local guild = client._sticker_map[sticker.id]
				return guild and guild._stickers:get(sticker.id) or nil
			else
				-- return client:getSticker(sticker.id) ??
			end
		end)
	end
	return self._stickers
end

There should be no reason to only load stickers of type 1, but I will look into it properly later.