Add more files in examples/ to CI (#34)

This PR sets up more files from `examples/` to be run on CI.

Since we didn't have these on CI, there was a regression in the parser
that is also fixed in this PR.

Also, if the snapshot test for `syntax.rs` fails, we now get a nicer
output (using a unified diff), rather than just dumping _everything_.

The mimalloc and nr examples suffer from issues when snapshot testing,
so I've added them as ignored tests with reminders of _why_. However, we
should not block this PR on fixing that, so that at least we start
getting the CI checks on the rest.

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Unreleased
 
+* Fix `FnSpec` parsing
+  - Despite Verus having deprecated `FnSpec` with the introduction of `spec_fn`, verusfmt still supports it for projects on older Verus
+* Fix idempotency issue of macro-items inside `verus!` inside in-file `mod`ules
+
 # v0.2.4
 
 * Move verusfmt to the verus-lang organization: https://github.com/verus-lang/verusfmt
@@ -18,7 +22,7 @@
 * Update handling for `fn_trait_types`
 * Add support for `const` params
 * Add support for `opens_invariants`
-* Improve handling of comples self-params (e.g., `tracked '&a self`)
+* Improve handling of complex self-params (e.g., `tracked '&a self`)
 * Introduce `#[verusfmt::skip]` (#31)
 * Add support for new `->` and `matches` expressions (#32)
 

Cargo.toml

@@ -35,6 +35,7 @@ tracing-subscriber = { version = "0.3.17" }
 
 [dev-dependencies]
 insta = { version = "1.30.0" }
+similar = { version = "2.2.1" }
 
 # Spend more time on initial compilation in exchange for faster runs
 [profile.dev.package.insta]