minor #16012 [Routing] Add ignoreAttributes to the documentation (lamasfoker)

This PR was merged into the 4.4 branch.

Discussion
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[Routing] Add ignoreAttributes to the documentation

Add the documentation for a missing redirect configuration as stated symfony/symfony#38069 (comment)

Commits
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e83469e Add ignoreAttributes to the documentation

Author: javiereguiluz

routing.rst

@@ -1366,6 +1366,8 @@ Use the ``RedirectController`` to redirect to other routes and URLs:
                 # * for temporary redirects, it uses the 307 status code instead of 302
                 # * for permanent redirects, it uses the 308 status code instead of 301
                 keepRequestMethod: true
+                # add this to remove the parameters when redirecting
+                ignoreAttributes: true
 
         legacy_doc:
             path: /legacy/doc