Update default.go

[ksaj]

Added an entry for invoking sbcl --script for .lisp files.

You could also do .lsp but sbcl users tend to use the full .lisp extension.

[wtetsu]

Thank you for the PR.

I have one concern about this PR. I'm not familiar with LISP, but my understanding is there are many implementations. In that case, it may not be good if the default settings have sbcl that is just one of the LISP implementations.