Backslash handling

[amadanmath]

javascript:
  let foo = "bar\nbaz";

currently erroneously renders as

  let foo = "bar
baz";

I believe the backslash in HTML (or JavaScript) should be passed literally, not interpreted as string escape by Crystal, except inside Crystal interopolation #{...}.

[jeromegn]

You're right.

I'm not sure when I'll get to it though. PRs are welcome!