Add comment to explain test condition

Signed-off-by: Keith Koskie <[email protected]>

Author: vkkoskie

cryptoki/src/types.rs

@@ -272,6 +272,7 @@ mod test {
 
     #[test]
     fn utc_time_convert_bad() {
+        // Year starts with a non-numeric value ('A')
         let invalid: [u8; 16] = [
             0x41, 0x39, 0x37, 0x30, 0x30, 0x31, 0x30, 0x31, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30,
             0x30, 0x30,