Plain text and HTML invitation email messages contain different content

The HTML version of an invitation:

> Hi there!
>
> chris (chris@chriscoyne.com) has invited you to the Keybase alpha.
>
> Since Keybase isn't even in beta, we are letting in very few people, and we have some hopes for the first few friends we let in.
> 1. Please make a complete profile (picture, bio, etc.), as you'll be an example to future beta users.
> 2. Please post or create a public key, and go through the identity proving process.
> 3. Please let us know if you encounter bugs or things that aren't clear.
>
> If that's all fair enough, you should accept chris's invitation.
>
> Here's the URL to accept:
>
> ```
> https://keybase.io/_/accept/...
> ```
>
> If you're using the command line version (instructions here) and want to paste the code in:
>
> ```
> ...
> ```
>
> Send us your feedback. We're working hard on it. Here's our repo, with links to our source code and our issue tracker: Keybase on Github
> - Max & Chris

The plain text version:

> Hi there!
>
> chris (chris@chriscoyne.com) has invited
> you to the Keybase alpha.
>
> Here's the URL to accept:
>
> ```
> https://keybase.io/_/accept/...
> ```
>
> If you're just going to use the command line version:
>
> ```
> Instructions: https://keybase.io/docs/command_line/prerequisites
> Your Invite Code: ...
> ```
>
> Send us your feedback! We're working hard on this alpha.
> - Max https://keybase.io/max
> - Chris https://keybase.io/chris

As you can see, the HTML version contains additional instructions about expectations for using Keybase and a link to the Github repository.

Compare the HTML and plain-text invitation email entry points to identify where their messages are assembled. Align the two versions so they contain the same invitation information, including the usage expectations and repository details, then verify both rendered outputs match in substance.

Written by the indexing model from the issue text.