minor #7292 Removed an unneeded note (javiereguiluz)

This PR was merged into the 2.7 branch.

Discussion
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Removed an unneeded note

This looks like a leftover of the old times when we didn't have a `services.yml` file and this config wasn't automatically imported.

Commits
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6a51cae Removed an unneeded note

Author: xabbuh

security/custom_provider.rst

@@ -211,11 +211,6 @@ Now you make the user provider available as a service:
     dependencies or configuration options or other services. Add these as
     arguments in the service definition.
 
-.. note::
-
-    Make sure the services file is being imported. See :ref:`service-container-imports-directive`
-    for details.
-
 Modify ``security.yml``
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