Expand description
Tidy check to ensure #[test] and #[bench] are not used directly inside core.
#![no_core] libraries cannot be tested directly due to duplicating lang
items. All tests and benchmarks must be written externally in core/{tests,benches}.
Outside of core tests and benchmarks should be outlined into separate files
named tests.rs or benches.rs, or directories named tests or benches unconfigured
during normal build.