Add to Snippet Extractor

[bushidocodes]

https://github.com/exercism/snippet-extractor/#add-your-language

I imagine we'd want to filter out comments and the normal boilerplate at the top of every module. If possible, it might be nice to filter across multi-lines until the closing parenthesis is found in case an S-Expression is broken across lines.

;;
(module
(import
(memory