Merge #216

216: fix unstable display for pin docs r=yoshuawuyts a=yoshuawuyts

On https://docs.rs/async-std/0.99.6/async_std/ `pin` is not properly showing up as "unstable" despite being guarded as such. This fixes that. Thanks!

Co-authored-by: Yoshua Wuyts <yoshuawuyts@gmail.com>

Author: bors[bot]

src/lib.rs

@@ -56,6 +56,7 @@ pub mod task;
 
 cfg_if! {
     if #[cfg(any(feature = "unstable", feature = "docs"))] {
+        #[cfg_attr(feature = "docs", doc(cfg(unstable)))]
         pub mod pin;
         mod vec;
         mod result;