`@__FILE__` and `@__DIR__` return "incorrect" path

[MichaelHatherly]

Strictly not incorrect since that's the temp file that the extension uses if I understand correctly, but incorrect in the sense that the behaviour is different compared to Pluto in the browser.

This is on version 0.1.1.

[fonsp]

Thanks! This should be fixable since we insert the LineNumberNodes ourselves 🌝

[pankgeorg]

I'll try to use the exact same file as VSCode uses, as @pfitzseb suggested in the first place. Hopefully this will solve both this and #22, if it works. Otherwise we'll have to do some LineNumberNode magic