chore: fix some minor typos in the comments (#7442)

Signed-off-by: shangchenglumetro <[email protected]>

tokio-util/tests/task_join_map.rs

@@ -330,7 +330,7 @@ async fn duplicate_keys2() {
         biased;
         res = map.join_next() => match res {
             Some((_key, res)) => panic!("Task {res:?} exited."),
-            None => panic!("Phantom task completeion."),
+            None => panic!("Phantom task completion."),
         },
         () = tokio::task::yield_now() => {},
     }

tokio/src/process/mod.rs

@@ -943,7 +943,7 @@ impl Command {
     /// Small indirection for the spawn implementations.
     ///
     /// This is introduced for [`Self::spawn`] and [`Self::spawn_with`] to use:
-    /// [`Self::spawn`] cannot depend directly on on [`Self::spawn_with`] since
+    /// [`Self::spawn`] cannot depend directly on [`Self::spawn_with`] since
     /// it is behind `tokio_unstable`. It also serves as a way to reduce
     /// monomorphization bloat by taking in an already-spawned child process
     /// instead of a command and custom spawn function.