Fix redirects URLs (#10259)

docs/redirects.txt

@@ -68,5 +68,5 @@ howto/operator/google/firebase/index.rst howto/operator/google/index.rst
 
 # Other redirects
 howto/operator/http/http.rst howto/operator/http.rst
-docs/howto/operator/http/index.rst howto/operator/http.rst
-docs/howto/use-alternative-secrets-backend.rst howto/altenative-secrets-backends/index.rst
+howto/operator/http/index.rst howto/operator/http.rst
+howto/use-alternative-secrets-backend.rst howto/secrets-backend/index.rst