minor #10806 better readability (OskarStark)

This PR was submitted for the master branch but it was merged into the 3.4 branch instead (closes #10806).

Discussion
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better readability

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Commits
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84249f9 better readability

Author: javiereguiluz

.symfony/routes.yaml

@@ -1,11 +1,11 @@
 https://{default}/:
   cache:
     cookies:
-    - '*'
+      - '*'
     default_ttl: 0
     enabled: true
     headers:
-    - Accept
-    - Accept-Language
+      - Accept
+      - Accept-Language
   type: upstream
   upstream: symfonydocs:http