Update cpp/includes/defines.h

Co-authored-by: Alex H. Room <69592136+alexhroom@users.noreply.github.com>

Author: StephenNneji

cpp/includes/defines.h

@@ -16,7 +16,7 @@ Parameters
 message : str
     The title text for the event.
 percent : float
-    The percentage of the calculation completed.
+    The percentage of the calculation completed (as a number between 0 and 1)
 )";
 
 struct ProgressEventData