doc: add comments to ConnWriteTimeout as a request timeout (#469)

* doc: add comments to connwritetimeout

* doc: fix wrong comments

rueidis.go

@@ -133,7 +133,9 @@ type ClientOption struct {
 	// The default for cluster clients is 0, which means 1 connection (2^0).
 	PipelineMultiplex int
 
-	// ConnWriteTimeout is applied net.Conn.SetWriteDeadline and periodic PING to redis
+	// ConnWriteTimeout is read/write timeout for each connection. If specified,
+	// it is used to control the maximum duration waits for responses to pipeline commands.
+	// Also, ConnWriteTimeout is applied net.Conn.SetDeadline and periodic PING to redis
 	// Since the Dialer.KeepAlive will not be triggered if there is data in the outgoing buffer,
 	// ConnWriteTimeout should be set in order to detect local congestion or unresponsive redis server.
 	// This default is ClientOption.Dialer.KeepAlive * (9+1), where 9 is the default of tcp_keepalive_probes on Linux.