This aligns the main error message a bit more with the phrasing in the
Edition Guide and provides a bit more information on the labels to
(hopefully!) aid in understanding.
Since there are so many ways to write these, I've opted to only include
two sorts of test: simple tests that directly target the rules differing
between rulesets and nuanced tests that produce different errors under
different rulesets. I've also tried not to add any duplicate tests.
`well-typed-edition-2024.rs` already has tests disagreeing with stable,
so I've opted not to include any in this commit that are well-typed
under the new rules.
This serves two purposes.
First, they're additional tests that stable Rust behavior hasn't been
messed with. There's plenty of other pattern tests, so this is less
important, but these at least are targeted at what's being changed.
Second, this helps document exactly where the new rulesets agree and
disagree with stable pattern typing. This will be especially important
after the new rules for old editions are updated, since they need to be
strictly more permissive; any patterns well-typed on stable should also
be well-typed with the same resultant bindings on the (upcoming) new new
old-edition rules.
The unusual test ordering on `borrowck-errors.rs` and
`ref-binding-on-inh-ref-errors.rs` are to hopefully reduce how much
adding new tests will mess with line numbers in their stderr.
