minor #20898 fix configuration block indentation (xabbuh)

This PR was merged into the 7.3 branch.

Discussion
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fix configuration block indentation

Commits
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c4cf202 fix configuration block indentation

Author: xabbuh

Diff for: service_container.rst

@@ -226,7 +226,7 @@ each time you ask for it.
     If some files or directories in your project should not become services, you
     can exclude them using the ``exclude`` option:
 
-        .. configuration-block::
+    .. configuration-block::
 
         .. code-block:: yaml