Fixes: https://github.com/zkat/miette/issues/408
Implement `WrapError` for `Option<T>`. This is inline with `anyhow` that
also implements `Context` for `Option<T>`.
The implementation requires us to introduce a `DisplayError` internal
only type, that creates an error from a type that only implements
`Display` (`Report::from_adhoc` requires the type to also implement
`Debug`, but `WrapError` only requires it to implement `Display`).
For this I copied `MessageError` and adapted it to implement `Debug`
using the underlying type's `Display` impl. This is a bit of a hack, but
anyhow does [something similar][1].
[1]: https://docs.rs/anyhow/latest/src/anyhow/wrapper.rs.html#34
This PR overhauls the toplevel/main experience for `miette`. It adds a new `Report` type based on `eyre::Report` and overhauls various types to fit into this model, as well as prepare for some [future changes in Rust](https://github.com/nrc/rfcs/pull/1) that will make it possible to integrate `miette` directly with crates like `eyre` instead of having to use this specific `Report`.
As such, this PR is a major breaking change, especially for anyone using `DiagnosticReport` and company.
BREAKING CHANGES:
* `DiagnosticReport` is now just `Report`, and is a different, `eyre::Report`-like type.
* `DiagnosticResult` is now just `Result`.
* `.into_diagnostic()` now just transforms the error into a `Report`.
* `DiagnosticReportPrinter` has been replaced with `ReportHandler`
* `set_printer` has been replaced by `set_hook`
* `code` is now optional.
* `.into_diagnostic()` no longer takes a `code` argument.
* `#[diagnostic]` is now optional when deriving `Diagnostic`.
Jalil David Salamé Messina
Nathan Whitaker
Kat Marchán