feature guard pin

Signed-off-by: Yoshua Wuyts <yoshuawuyts@gmail.com>

Author: yoshuawuyts

src/lib.rs

@@ -53,6 +53,7 @@ pub mod sync;
 pub mod task;
 
 #[cfg_attr(feature = "docs", doc(cfg(unstable)))]
+#[cfg(feature = "unstable")]
 pub mod pin;
 
 pub(crate) mod utils;