adapter - add doc-test attribute to enable the dummy-adapter feature

Author: elpiel

adapter/src/lib.rs

@@ -1,5 +1,6 @@
 #![deny(rust_2018_idioms)]
 #![deny(clippy::all)]
+#![doc(test(attr(cfg(feature = "dummy-adapter"))))]
 pub use self::adapter::*;
 pub use self::sanity::*;