docs(options1): fix and clarify 24 hour time instruction

Author: bhbuehler

exercises/options/options1.rs

@@ -8,8 +8,8 @@
 // all, so there'll be no more left :(
 // TODO: Return an Option!
 fn maybe_icecream(time_of_day: u16) -> Option<u16> {
-    // We use the 24-hour system here, so 10PM is a value of 22
-    // The Option output should gracefully handle cases where time_of_day > 24.
+    // We use the 24-hour system here, so 10PM is a value of 22 and 12AM is a value of 0
+    // The Option output should gracefully handle cases where time_of_day > 23.
     ???
 }