minor #17525 [Validator] Better wording (dragonito)

This PR was submitted for the 6.2 branch but it was merged into the 5.4 branch instead.

Discussion
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[Validator] Better wording

Found once more. The other "to validate" in this text are fine.

Commits
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49e516a Better wording

Author: javiereguiluz

components/validator/metadata.rst

@@ -67,7 +67,7 @@ Then, add the Validator component configuration to the class::
 Classes
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-Some constraints allow to validate the entire object. For example, the
+Some constraints allow validating the entire object. For example, the
 :doc:`Callback </reference/constraints/Callback>` constraint is a generic
 constraint that's applied to the class itself.