message: Add missing link to `CONTRIBUTING`
diff: @@ -29,3 +29,4 @@ Moreover, Iced is in its infancy and, besides directly writing code, there are m
  [Zulip server]: https://iced.zulipchat.com/
  [Code is the Easy Part]: https://youtu.be/DSjbTC-hvqQ?t=1138
  [The Hard Parts of Open Source]: https://www.youtube.com/watch?v=o_4EX4dPppA
  +[`wgpu_glyph`]: https://github.com/hecrj/wgpu_glyph
  