Fix detection of << end.

[Kentzo]

Before:

After:

[alexlouden]

Hey @Kentzo thanks for this! Resolves #23

[Kentzo]

@alexlouden I'll be working with TF for some time and would love to address what I can.
If you have time, please add issues so I could work through them.

[alexlouden]

Oh awesome, that'd be great. I've been hoping to build in more TF/Consul syntax and make it a bit more user friendly, but I can't think of anything major at the moment. I've recently added TF keywords, and I was thinking about highlighting invalid syntax (missing closing braces, etc).

Do you use bash scripts in your heredoc - I think it's possible to fall back to the bash syntax language within e.g. <<SHELL?

Keen to hear any suggestions you have (or anyone else reading this has) too!

[Kentzo]

@alexlouden I'm not aware of any consistent usage of <<SHELL, and google doesn't show any results. In other hand I seldom use <<.