Update documentation link to the component

Update documentation link to the component since it has standalone examples

Author: CoolGoose

src/Symfony/Component/Validator/README.md

@@ -7,7 +7,7 @@ The Validator component provides tools to validate values following the
 Resources
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-  * [Documentation](https://symfony.com/doc/current/book/validation.html)
+  * [Documentation](https://symfony.com/doc/current/components/validator.html)
   * [Contributing](https://symfony.com/doc/current/contributing/index.html)
   * [Report issues](https://github.com/symfony/symfony/issues) and
     [send Pull Requests](https://github.com/symfony/symfony/pulls)