Add newly introduced functions

[totoroot]

I noticed that some recently added functions were not highlighted correctly so I went ahead and added them.

Personally I do not use Sublime but took a closer look at this, when I added syntax highlighting of Terraform files to micro editor.

The relevant official documentation can be found here: https://www.terraform.io/docs/language/functions/index.html

[totoroot]

Why would the syntax tests fail?