docs: fix format of lb API comments (#29126)

Signed-off-by: wbpcode <wangbaiping@corp.netease.com>

Mirrored from https://github.com/envoyproxy/envoy @ 76ade2a8ac9b92f93028cfbd6ab507e8a69456d3

envoy/extensions/load_balancing_policies/cluster_provided/v3/cluster_provided.proto

@@ -17,7 +17,7 @@ option (udpa.annotations.file_status).package_version_status = ACTIVE;
 // If this extension is configured, the target cluster must provide load balancer when the cluster
 // is created.
 //
-// ..note::
+// .. note::
 //   Cluster provided load balancing policy could not be used as sub-policy of other hierarchical
 //   load balancing policies, such as subset load balancing policy.
 message ClusterProvided {

envoy/extensions/load_balancing_policies/ring_hash/v3/ring_hash.proto

@@ -56,7 +56,7 @@ message RingHash {
   // If set to `true`, the cluster will use hostname instead of the resolved
   // address as the key to consistently hash to an upstream host. Only valid for StrictDNS clusters with hostnames which resolve to a single IP address.
   //
-  // ..note::
+  // .. note::
   //   This is deprecated and please use :ref:`consistent_hashing_lb_config
   //   <envoy_v3_api_field_extensions.load_balancing_policies.ring_hash.v3.RingHash.consistent_hashing_lb_config>` instead.
   bool use_hostname_for_hashing = 4
@@ -79,7 +79,7 @@ message RingHash {
   // This is an O(N) algorithm, unlike other load balancers. Using a lower `hash_balance_factor` results in more hosts
   // being probed, so use a higher value if you require better performance.
   //
-  // ..note::
+  // .. note::
   //   This is deprecated and please use :ref:`consistent_hashing_lb_config
   //   <envoy_v3_api_field_extensions.load_balancing_policies.ring_hash.v3.RingHash.consistent_hashing_lb_config>` instead.
   google.protobuf.UInt32Value hash_balance_factor = 5 [