minor #8288 Update NotIdenticalTo.rst (Sakulbl)

This PR was submitted for the 2.8 branch but it was merged into the 2.7 branch instead (closes #8288).

Discussion
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Update NotIdenticalTo.rst

Fixed message option explanation of NotIdenticalTo validation constraint

Commits
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a0a8834 Update NotIdenticalTo.rst

Author: xabbuh

reference/constraints/NotIdenticalTo.rst

@@ -121,6 +121,6 @@ message
 
 **type**: ``string`` **default**: ``This value should not be identical to {{ compared_value_type }} {{ compared_value }}.``
 
-This is the message that will be shown if the value is not equal.
+This is the message that will be shown if the value is identical.
 
 .. include:: /reference/constraints/_payload-option.rst.inc