dillon1000/react

[rust] General-purpose diagnostic type and helpers

This PR adapts the `Diagnostic` type and helpers from Relay Compiler to Forget. 
The main changes are: 

* Removing some fields it doesn't seem we'll use for a while, if ever (like 
machine-readable arbitrary key/value data) 

* Switching from Relay Compiler's `Location` type to our SourceRange type 

* Using the severity enum previously established in the `forget_build_hir` 
crate, with Todo/Unsupported/InvalidSyntax/InvalidReact/Invariant variants 

* Adding support for translating our `Diagnostic` into a `miette::Diagnostic` so 
we can use miette's pretty printing 

With the new Diagnostic type in place i updated the existing build_hir code to 
use it and confirmed that the errors are now even nicer (when we attach extra 
data to annotate labels): 

<img width="860" alt="Screenshot 2023-07-14 at 3 10 00 PM" 
src="https://github.com/facebook/react-forget/assets/6425824/9d29425a-938b-4872-b999-aa174a3c329a"> 

This addresses (or brings us closer to addressing) many of your comments on the 
last diagnostics PR, @poteto!