The new test command added in e0c627b directly followed the prior
command, without `&&`-chaining the result. So if the tests before it
_failed_, we wouldn't notice...

ci: make sure test commands are `&&`-chained

The edition works automatically when running `cargo fmt`, but not when
running `rustfmt` directly as some editors do.

If you know you need "std", e.g. relying on default `S = RandomState`,
then you can enable this feature to force it on, bypassing target
detection. This may help scenarios where `autocfg` fails detection, like
issue #144, but at the very least it will speed up the build script by
avoiding extra `rustc` invocations.

Add a feature to explicitly enable "std"

Update to hashbrown 0.9