refactor(MessageReaction): ReactionUserStore (#2078)

* refactor(MessageReactions): fetchUsers() is now users.fetch()

made a lovely class for it and all
happify linter


stuff


i know how to code i swear


i lied

* bdistin suggestions

* space suggestions, rename store

* fix count

* documentation update

src/index.js

@@ -29,6 +29,7 @@ module.exports = {
   GuildChannelStore: require('./stores/GuildChannelStore'),
   GuildMemberStore: require('./stores/GuildMemberStore'),
   GuildStore: require('./stores/GuildStore'),
+  ReactionUserStore: require('./stores/ReactionUserStore'),
   MessageStore: require('./stores/MessageStore'),
   PresenceStore: require('./stores/PresenceStore'),
   RoleStore: require('./stores/RoleStore'),