Add a better emoji picker #2890

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Hi,

The current way of using emojis on GitHub is not that great. You start typing : and don't get a lot of choices.

See:

My current workaround is to go to this gist, listing all emojis: https://gist.github.com/rxaviers/7360908 which is not ideal.

It would be nice to have a real emoji picker. A cool feature would be a search box, last used emojis, categories...

Have a nice day :bowtie: :relieved: :blush: