chore: slight re-wording of unconstrained's module docs
//!
//! #### unconstrained
//!
-//! If necessary, [`task::unconstrained`] lets you opt out a future of Tokio's cooperative
+//! If necessary, [`task::unconstrained`] lets you opt a future out of of Tokio's cooperative
//! scheduling. When a future is wrapped with `unconstrained`, it will never be forced to yield to
//! Tokio. For example:
//!
