minor #5200 Added missing link in "Sections" (sfdumi)

This PR was merged into the 2.3 branch.

Discussion
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Added missing link in "Sections"

Commits
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a63b9b9 Added missing link in "Sections"

Author: wouterj

components/security/introduction.rst

@@ -25,5 +25,6 @@ Sections
 * :doc:`/components/security/firewall`
 * :doc:`/components/security/authentication`
 * :doc:`/components/security/authorization`
+* :doc:`/components/security/secure_tools`
 
 .. _Packagist: https://packagist.org/packages/symfony/security