Multiline string support

[spenceral]

Hello! Can hclencoder encode multiline strings? If not, can I submit a PR that will not quote strings that are prefixed with <<? I believe that allow multiline strings to be encoded properly as long as the user has submitted a string in heredoc format.

[rodaine]

Howdy! I'm not sure if we have any tests for multiline strings, but if it's not encoding them properly (or if it's slapping \n everywhere), it's probably best to support the heredoc format. I don't think we should treat strings beginning with << as special though.

If you want to take a stab at this, I'd recommend detecting if a string contains \n before encoding, if it does, output in a heredoc format instead, with some default sentinel (perhaps EOF) which can be overridden with an hcle struct tag. Thoughts?

[spenceral]

As far as I can tell, it is not encoding multiline strings properly as it handling the string like any other primitive string, e.g.

foo = "asdf
hjkl"

Rather than encoding it in the heredoc format, e.g.

foo = <<EOF
asdf
hjkl
EOF

Your approach sounds better than looking for a "<<" prefix. I'll take a stab at it.