title: Discord.js message.react fails when adding specific unicode emotes
body: <p>Yesterday I started coding a bot using the guide from discord.js. <a href="https://github.com/discordjs/guide/tree/master/code_samples/command-handling/file-setup" rel="noreferrer">The core</a> is just with what you finish the Command Handler part with.<br>
  I was working on a voting command, where the bot would react with Unicode symbols like :one: :two: :three:.<br>
  This is where I encounter my problem. Using:</p>
  
  <pre><code>module.exports = {
  name: 'testing',
  description: 'creates a reaction',
  aliases: ['test'],
  cooldown: 1,
  execute(message, args) {
      if (!args.length) {
          message.react(':one:');
      }      
  }
  </code></pre>
  
  <p>};
  Gives me a <code>DiscordAPIError: Unknown Emoji</code>  </p>
  
  <p>I spend some time trying different emotes like  and they are working as expected. Using the emote ID (422515569623957504) does not work as well for me.   </p>
  
  <p>Is this a mistake on my side or a bug?</p>