feat(compiler): rework diagnostics to support multiple files

[goto-bus-stop]

miette doesn't support referencing multiple files in one error, so we sadly can't use it directly. Most errors in executable documents will reference another document.

Without miette's derives, we need some other way to represent shared diagnostic properties like labels and help text. For now this PR uses:

pub struct ApolloDiagnostic {
    pub location: HirNodeLocation, // ← may be removed as the first Label will usually have the same location
    pub labels: Vec<Label>,
    pub help: Option<String>,
    pub data: DiagnosticData,
}

DiagnosticData is an enum with the different diagnostic types and specific information about them.
With that structure we need to format labels wherever we create an error.

I converted a part of the validation so far and explored using ariadne for displaying errors. I'll continue to work on ariadne output first in case the diagnostic data structure needs to change. Then some API polish, maybe we can reduce the boilerplatyness of this implementation a bit.

Todos:

• We need an ariadne release (using a fork)
• Tests now rely on the order they are run in to work, due to the global FileId counter -- they should be checked some other way. Maybe ApolloDiagnostic Debug impl can censor them consistently or we just make FileId display as a constant value … or we change the test output to use source strings wherever a DiagnosticLocation occurs … or something else
  Reset FileId between directory tests #437

[goto-bus-stop]

Something still wrong in printing the line/column offsets, but this is an example of a multi-file diagnostic:

[lrlna]

ooooohh that is already looking real good @goto-bus-stop !

[goto-bus-stop]

OK, we're really getting somewhere:

Time to resolve some conflicts ;p

[goto-bus-stop]

This can be reviewed but it still has some blockers, will maintain checklist in OP

[lrlna]

is there a way to get ariadne to expand its spans?

There are a couple of places where the fields get swallowed when diagnostics are expanded, and the error becomes a lot more confusing.

Some examples:

duplicate names with miette

duplicate names with ariadne

expected ident with miette

expected ident with ariadne

unexpected field with miette

unexpected field with ariadne

(nice addition of original Query definition here though ;)

[lrlna]

some error standardisation here

[goto-bus-stop]

so at this stage it works and everything, but we have less context in error messages.

[lrlna]

@goto-bus-stop ok, let's merge this in, and in our continued validation process work on adding more context to ariadne