Update join_set.rs

Co-authored-by: Motoyuki Kimura <[email protected]>

tokio/src/task/join_set.rs

@@ -375,8 +375,8 @@ impl<T: 'static> JoinSet<T> {
     }
 
     /// Awaits the completion of all tasks in this `JoinSet`, returning a vector of their results.
-    /// The results will be stored in the order they completed not the order they were spawned.
     ///
+    /// The results will be stored in the order they completed not the order they were spawned.
     /// This is a convenience method that is equivalent to calling [`join_next`] in
     /// a loop. If any tasks on the `JoinSet` fail with an [`JoinError`], then this call
     /// to `join_all` will panic and all remaining tasks on the `JoinSet` are