minor #16993 Updating Link (ThomasLandauer)

This PR was merged into the 5.4 branch.

Discussion
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Updating Link

Commits
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a31ba86 Updating Link

Author: javiereguiluz

reference/constraints/Email.rst

@@ -145,4 +145,4 @@ configuration option.
 
 .. _egulias/email-validator: https://packagist.org/packages/egulias/email-validator
 .. _HTML5 email input element: https://www.w3.org/TR/html5/sec-forms.html#valid-e-mail-address
-.. _RFC 5322: https://tools.ietf.org/html/rfc5322
+.. _RFC 5322: https://datatracker.ietf.org/doc/html/rfc5322