add a note about the default inbound interception mode (#2913)

* add a note about the default mode

* include generated html

Author: rsalmond

mesh/v1alpha1/istio.mesh.v1alpha1.pb.html

@@ -461,7 +461,7 @@ message ProxyConfig {
   // outbound connections.
   enum InboundInterceptionMode {
     // The `REDIRECT` mode uses iptables `REDIRECT` to `NAT` and redirect to Envoy. This mode loses
-    // source IP addresses during redirection.
+    // source IP addresses during redirection. This is the default redirection mode.
     REDIRECT = 0;
     // The `TPROXY` mode uses iptables `TPROXY` to redirect to Envoy. This mode preserves both the
     // source and destination IP addresses and ports, so that they can be used for advanced