fix: gives a bit more context to magic number
// threads1.rs
// Make this compile! Execute `rustlings hint threads1` for hints :)
// The idea is the thread spawned on line 21 is completing jobs while the main thread is
-// monitoring progress until 10 jobs are completed. If you see 6 lines
+// monitoring progress until 10 jobs are completed. Because of the difference between the
+// spawned threads' sleep time, and the waiting threads sleep time, when you see 6 lines
// of "waiting..." and the program ends without timing out when running,
// you've got it :)
