Switch to using GitHub's Emoji set.

Review Request #9308 — Created Oct. 23, 2017 and submitted — Latest diff uploaded


Review Board


The initial introduction of our new Emoji support was using EmojiOne's
free/open source license. This license requires attribution in some
form, and while their license doesn't mandate an exact way to do this,
their example placement for attribution (at the bottom of every page or
right below where Emojis will show), it's not clear whether we have a
suitable option that will fully be compliant now and going forward.

Instead, we're moving to GitHub's Gemoji set, which has a suitable
license and will provide an icon set familiar to many developers out

Tested various Emoji and made sure they worked correctly.