revert stabilization of core::task::ready!

Author: ibraheemdev

library/core/src/task/mod.rs

@@ -11,7 +11,7 @@ mod wake;
 pub use self::wake::{Context, RawWaker, RawWakerVTable, Waker};
 
 mod ready;
-#[stable(feature = "ready_macro", since = "1.56.0")]
+#[unstable(feature = "ready_macro", issue = "70922")]
 pub use ready::ready;
 #[unstable(feature = "poll_ready", issue = "none")]
 pub use ready::Ready;

library/core/src/task/ready.rs

@@ -50,7 +50,7 @@ use core::task::Poll;
 ///     # Poll::Ready(())
 /// # }
 /// ```
-#[stable(feature = "ready_macro", since = "1.56.0")]
+#[unstable(feature = "ready_macro", issue = "70922")]
 #[rustc_macro_transparency = "semitransparent"]
 pub macro ready($e:expr) {
     match $e {