[skip ci]Add etcd config comment (#10617)

Signed-off-by: xiaofan-luan <xiaofan.luan@zilliz.com>

configs/advanced/etcd.yaml

@@ -15,6 +15,8 @@
 # limitations under the License.
 
 # This is the configuration file for the etcd server.
+# Only standalone users with embeded etcd should change this file, others could just keep this file As Is.
+# All the etcd client should be added to milvus.yaml if necessary
 
 # Human-readable name for this member.
 name: 'default'