HDFS-16255. RBF: Fix dead link to fedbalance document (#4193)

Signed-off-by: Akira Ajisaka <aajisaka@apache.org>

hadoop-hdfs-project/hadoop-hdfs-rbf/src/site/markdown/HDFSRouterFederation.md

@@ -527,7 +527,7 @@ More metrics info can see [RBF Metrics](../../hadoop-project-dist/hadoop-common/
 Router Federation Rename
 -------
 
-Enable Router to rename across namespaces. Currently it is implemented based on [HDFS Federation Balance](../../../hadoop-federation-balance/HDFSFederationBalance.md) and has some limits comparing with normal rename.
+Enable Router to rename across namespaces. Currently it is implemented based on [HDFS Federation Balance](../../hadoop-federation-balance/HDFSFederationBalance.md) and has some limits comparing with normal rename.
 1. It is much slower than the normal rename so need a longer RPC timeout configuration. See `ipc.client.rpc-timeout.ms` and its description for more information about RPC timeout.
 2. It doesn't support snapshot path.
 3. It doesn't support to rename path with multiple destinations.