fix two futex comments

Author: joboet

src/shims/unix/macos/sync.rs

@@ -132,6 +132,10 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
 
         let is_shared = flags == shared;
         let timeout = clock_timeout.map(|(_, anchor, timeout)| {
+            // The only clock that is currenlty supported is the monotonic clock.
+            // While the deadline argument of `os_sync_wait_on_address_with_deadline`
+            // is actually not in nanoseconds but in the units of `mach_current_time`,
+            // the two are equivalent in miri.
             (TimeoutClock::Monotonic, anchor, Duration::from_nanos(timeout))
         });
 

tests/pass-dep/concurrency/apple-futex.rs

@@ -6,7 +6,7 @@ use std::{io, ptr, thread};
 fn wake_nobody() {
     let futex = 0;
 
-    // Wake 1 waiter. Expect ENOENT woken up, as nobody is waiting.
+    // Wake 1 waiter. Expect ENOENT as nobody is waiting.
     unsafe {
         assert_eq!(
             libc::os_sync_wake_by_address_any(