api: fix comment for PrefetchPolicy (#12955)

* grammar fix
* small style fix splitting sentence up

Signed-off-by: Raul Gutierrez Segales <rgs@pinterest.com>

Mirrored from https://github.com/envoyproxy/envoy @ 3a5d691e582e360bb1a35272e4972984937e7d6a

envoy/config/cluster/v3/cluster.proto

@@ -577,9 +577,9 @@ message Cluster {
 
   // [#not-implemented-hide:]
   message PrefetchPolicy {
-    // Indicates how many many streams (rounded up) can be anticipated per-upstream for each
-    // stream, useful for high-QPS or latency-sensitive services. Prefetching will only be done if
-    // the upstream is healthy.
+    // Indicates how many streams (rounded up) can be anticipated per-upstream for each
+    // incoming stream. This is useful for high-QPS or latency-sensitive services. Prefetching
+    // will only be done if the upstream is healthy.
     //
     // For example if this is 2, for an incoming HTTP/1.1 stream, 2 connections will be
     // established, one for the new incoming stream, and one for a presumed follow-up stream. For

envoy/config/cluster/v4alpha/cluster.proto

@@ -584,9 +584,9 @@ message Cluster {
     option (udpa.annotations.versioning).previous_message_type =
         "envoy.config.cluster.v3.Cluster.PrefetchPolicy";
 
-    // Indicates how many many streams (rounded up) can be anticipated per-upstream for each
-    // stream, useful for high-QPS or latency-sensitive services. Prefetching will only be done if
-    // the upstream is healthy.
+    // Indicates how many streams (rounded up) can be anticipated per-upstream for each
+    // incoming stream. This is useful for high-QPS or latency-sensitive services. Prefetching
+    // will only be done if the upstream is healthy.
     //
     // For example if this is 2, for an incoming HTTP/1.1 stream, 2 connections will be
     // established, one for the new incoming stream, and one for a presumed follow-up stream. For