Steps to Reproduce:

I suspect this could be an Electron/Chromium issue, since the pepper emoji is relatively new.
This should be marked as critical 馃槶
Each OS has its own Emoji set and the Pepper falls back to system one as Chromium56 doesn't have that. But if you look at emojis on macOS, you can notice they are different as well, and still colorful.

We should verify this issue in next Electron update.
Like the https://github.com/electron/electron/issues/7334#issuecomment-250611191
More details here, Pepper is introduced in Unicode v7 (https://commons.wikimedia.org/wiki/Emoji) and Chromium is not always picking up the latest so in M56 Chromium doesn't think it's an Emoji, https://bugs.chromium.org/p/chromium/issues/detail?id=617631&q=segoe%20ui%20emoji&colspec=ID%20Pri%20M%20Stars%20ReleaseBlock%20Component%20Status%20Owner%20Summary%20OS%20Modified
To mitigate this issue, you may want to set your editor.fontFamily to use an emoji font.
Can confirm, adding "Segoe UI Emoji" to the end of my editor.fontFamily setting makes the pepper emoji 馃尪 show up in full color 馃槃
{
"editor.fontFamily": "Fira Code, Consolas, Segoe UI Emoji"
}

Can VSCode always append that font automatically (and the appropriate OS X and Linux fonts) to the setting behind the scenes as a fallback, when rendering the text editor? That way we don't depend on Chromium's emoji presentation defaults.
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This should be marked as critical 馃槶