bug #5815 fix constraint names (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
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fix constraint names

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets |

Commits
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4e550ec fix constraint names

reference/constraints/map.rst.inc

@@ -7,9 +7,9 @@ the value of properties or the return value of methods on your object.
 * :doc:`NotBlank </reference/constraints/NotBlank>`
 * :doc:`Blank </reference/constraints/Blank>`
 * :doc:`NotNull </reference/constraints/NotNull>`
-* :doc:`Null </reference/constraints/IsNull>`
-* :doc:`True </reference/constraints/IsTrue>`
-* :doc:`False </reference/constraints/IsFalse>`
+* :doc:`IsNull </reference/constraints/IsNull>`
+* :doc:`IsTrue </reference/constraints/IsTrue>`
+* :doc:`IsFalse </reference/constraints/IsFalse>`
 * :doc:`Type </reference/constraints/Type>`
 
 String Constraints