update acorn and parse expression as module script

[tanhauhau]

Fixes #5422
Fixes #5407

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Tests

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[Conduitry]

With this PR and with {import.meta.url} in the template, the compiler gives missing-declaration warnings about import and (strangely) meta. I don't know whether we want to handle this by adding import to the known globals, or whether we want to special-case this, and I also don't know why it's warning us about meta.

[antony]

I think import.meta is for this specific purpose, for magic Schrodinger's variables and such, so it should probably be special cased?

[tanhauhau]

hmm.. let me add a test case to make sure that it didnt have warning. 🤔