[refactor] _PrintWithSpanId -> _PrintWithLocation

[abathur]

This bite is a little bigger (and more complex) than I really wanted to take, so my confidence is only moderate. Be skeptical :)

[andychu]

Thanks for looking at this!

Now that I think about it, I said we were going to remove loc.Span(). That's true long term, but short term we're going to INTRODUCE loc.Span(), because it's a trivial wrapper around a span_id that lets us do the type-driven refactoring.

It would be nice to "pull the band-aid off all at once", but now that I look at it, we have to do it two steps:

1. Change APIs to take loc_t, and pass loc.Span(span_id) mechanically
2. Later get rid of `loc.Span()

The reason is that there are simply a lot of usages! This command shows there are 677 !! Location info is all over the codebase, because that's how we get fine-grained error messages.

$ metrics/source-code.sh osh-files | xargs egrep 'span_id|spid'  | wc -l
677

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So I think I found a tinier piece to bite off. Take a look at this PR:

#1491

And maybe try the same thing for one of the other methods Print_() or PrintMessage()

I think those will be smaller bites and we can lean on the type system more. (Although leaning on the CI is also OK!)

Thanks