Add Mastodon icon??

[Vctrsnts]

Hi, And firts, thanks for this theme.

I trying to add mastodon icon modify de file /_sass/_icons.scss and add this code:

.fa-mastodon:before {
  content: "\f4f6";
}

But when refresh the page I see the code f4f6, not the icon, and the code is the same to use for github icon:

.fa-github:before {
  content: "\f09b";
}

But with the code to this page that is the same for use the github icon

Where is the problem? How I add the Mastodon Icon on this theme?

Because I trying to download new fonts about Awesome, but not solution this problem.

Thanks for all