Use `f` instead of `|| f()`.

Co-authored-by: NMark Rousskov <mark.simulacrum@gmail.com>

library/std/src/thread/scoped.rs

@@ -231,7 +231,7 @@ pub fn spawn_scoped<'scope, 'env, F, T>(
         F: FnOnce() -> T + Send + 'scope,
         T: Send + 'scope,
     {
-        Ok(ScopedJoinHandle(unsafe { self.spawn_unchecked_(|| f(), Some(&scope.data)) }?))
+        Ok(ScopedJoinHandle(unsafe { self.spawn_unchecked_(f, Some(&scope.data)) }?))
     }
 }