ci: add spellchecking (#6297)

tokio/src/runtime/blocking/pool.rs

@@ -105,16 +105,16 @@ struct Shared {
     num_notify: u32,
     shutdown: bool,
     shutdown_tx: Option<shutdown::Sender>,
-    /// Prior to shutdown, we clean up JoinHandles by having each timed-out
+    /// Prior to shutdown, we clean up `JoinHandles` by having each timed-out
     /// thread join on the previous timed-out thread. This is not strictly
     /// necessary but helps avoid Valgrind false positives, see
     /// <https://github.com/tokio-rs/tokio/commit/646fbae76535e397ef79dbcaacb945d4c829f666>
     /// for more information.
     last_exiting_thread: Option<thread::JoinHandle<()>>,
-    /// This holds the JoinHandles for all running threads; on shutdown, the thread
+    /// This holds the `JoinHandles` for all running threads; on shutdown, the thread
     /// calling shutdown handles joining on these.
     worker_threads: HashMap<usize, thread::JoinHandle<()>>,
-    /// This is a counter used to iterate worker_threads in a consistent order (for loom's
+    /// This is a counter used to iterate `worker_threads` in a consistent order (for loom's
     /// benefit).
     worker_thread_index: usize,
 }