Equals updates (#987)

* Docs update

Changed the param names and param descriptions to be consistent.

* Added === comparison

Changed Presence.equals and Game.equals to first compare using ===

* Collection.equals fix

Now returns false when collection is undefined, instead of crashing
💯

src/structures/GroupDMChannel.js

@@ -89,7 +89,7 @@ class GroupDMChannel extends Channel {
    * Whether this channel equals another channel. It compares all properties, so for most operations
    * it is advisable to just compare `channel.id === channel2.id` as it is much faster and is often
    * what most users need.
-   * @param {GroupDMChannel} channel The channel to compare to
+   * @param {GroupDMChannel} channel Channel to compare with
    * @returns {boolean}
    */
   equals(channel) {