Don't expand large gists/embeds - leave as a link

When I want to share code ~5 lines, I put it in a code block When I want to share something bigger, I put it in a gist.

But gitter pastes the gist into the window.

I would like gitter to not paste the code into the window if it is bigger than some small threshold (possibly 5 lines)

It would also be nice to be able to collapse this code that was auto included

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Relevant code: look for "iframely"