Better grammatical wording

Author: dragonito

components/validator/metadata.rst

@@ -37,7 +37,7 @@ Getters
 
 Constraints can also be applied to the value returned by any public *getter*
 method, which are the methods whose names start with ``get``, ``has`` or ``is``.
-This feature allows to validate your objects dynamically.
+This feature allows validating your objects dynamically.
 
 Suppose that, for security reasons, you want to validate that a password field
 doesn't match the first name of the user. First, create a public method called