Update Contest_API.md

Co-authored-by: Jaap Eldering <eldering@users.noreply.github.com>

Author: niemela

Contest_API.md

@@ -761,7 +761,7 @@ Properties of contest objects:
 
 The typical use of `countdown_pause_time` is when a contest director wishes to pause the countdown to the start of a contest.  For example, this may occur because of technical
 issues or to make an announcement.  When the contest countdown is paused, the value of `countdown_pause_time` should be set to the expected time remaining before the start of the contest after the pause is lifted.
-In this case, the `start_time` must be set to `null`, thereby, setting an undefined `start_time` (the `start_time` is undefined since
+If `countdown_pause_time` is set, then the `start_time` must be set to `null`, thereby, setting an undefined `start_time` (the `start_time` is undefined since
 the length of the pause may be unknown).
 The `countdown_pause_time` may be changed to indicate the approximate delay until the contest starts.
 Countdown is resumed by setting a new `start_time` and resetting