Replace "set leave" with leave only

Author: tybulewicz

reference/constraints/Image.rst

@@ -294,7 +294,7 @@ allowSquare
 **type**: ``Boolean`` **default**: ``true``
 
 If this option is false, the image cannot be a square. If you want to force
-a square image, then set leave this option as its default ``true`` value
+a square image, then leave this option as its default ``true`` value
 and set `allowLandscape`_ and `allowPortrait`_ both to ``false``.
 
 allowLandscape