minor #14747 [FrameworkBundle] Config reference for Secrets (Nyholm)

This PR was squashed before being merged into the 4.4 branch.

Discussion
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[FrameworkBundle] Config reference for Secrets

Commits
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c2500f9 [FrameworkBundle] Config reference for Secrets

Author: OskarStark

reference/configuration/framework.rst

@@ -197,6 +197,12 @@ Configuration
   * `utf8`_
 
 * `secret`_
+* `secrets`_
+
+  * `decryption_env_var`_
+  * `local_dotenv_file`_
+  * `vault_directory`_
+
 * `serializer`_
 
   * :ref:`circular_reference_handler <reference-serializer-circular_reference_handler>`
@@ -2483,6 +2489,31 @@ annotation changes). For performance reasons, it is recommended to disable
 debug mode in production, which will happen automatically if you use the
 default value.
 
+
+secrets
+~~~~~~~
+
+decryption_env_var
+..................
+
+**type**: ``string`` **default**: ``base64:default::SYMFONY_DECRYPTION_SECRET``
+
+The environment variable that contains the decryption key.
+
+local_dotenv_file
+.................
+
+**type**: ``string`` **default**: ``%kernel.project_dir%/.env.%kernel.environment%.local``
+
+Path to an dotenv file that holds secrets. This is primarily used for testing.
+
+vault_directory
+...............
+
+**type**: ``string`` **default**: ``%kernel.project_dir%/config/secrets/%kernel.environment%``
+
+The directory where the vault of secrets is stored.
+
 .. _configuration-framework-serializer:
 
 serializer