[Feature]: More context in error with big span

[nicolaassolini-qntm]

Can we get this line a bit more context, i.e. the two above it as well? Just the "pass" is maybe a bit confusing. But this is not really urgent.

Originally posted by @maximilianruesch in #2274 (comment)

This requires changing the diagnostic logic (maybe introducing a flag to show more lines or changing the number of lines that are shown when the span is big?).