net/http/httptest: doc tweaks

From lost-in-flight comments on CL 32190.

Change-Id: I2029cbac6d24b5944a796b359080011ec3a8da92
Reviewed-on: https://go-review.googlesource.com/32210Reviewed-by: Caleb Spare <cespare@gmail.com>
Reviewed-by: Martin Möhrmann <martisch@uos.de>

src/net/http/httptest/recorder.go

@@ -29,8 +29,8 @@ type ResponseRecorder struct {
 	// automatic Content-Type), use the Result method.
 	HeaderMap http.Header
 
-	// Body is the buffer that a Handler's Write calls are sent to.
-	// If nil, the Writes are silently discard.
+	// Body is the buffer to which the Handler's Write calls are sent.
+	// If nil, the Writes are silently discarded.
 	Body *bytes.Buffer
 
 	// Flushed is whether the Handler called Flush.