dart:io HttpServer.serverHeader - tweaks to doc comments

sdk/lib/io/http.dart

Index: sdk/lib/io/http.dart
diff --git a/sdk/lib/io/http.dart b/sdk/lib/io/http.dart
index 371543fa505218bff53794166aa9ea4a4292729d..21b177d84eaf5a41d1b6daf9e5904a4a2b41326f 100644
--- a/sdk/lib/io/http.dart
+++ b/sdk/lib/io/http.dart
@@ -94,9 +94,9 @@ abstract class HttpStatus {
  * Use [bindSecure] to create an HTTPS server.
  *
  * The server presents a certificate to the client. In the following
- * example, the certificate is named `localhost_cert` and comes from 
+ * example, the certificate is named `localhost_cert` and comes from
  * the database found in the `pkcert` directory.
- * 
+ *
  *     import 'dart:io';
  *     import "dart:isolate";
  *
@@ -145,7 +145,7 @@ abstract class HttpStatus {
  * * HttpServer is a Stream. Refer to the [Stream] class for information
  * about the streaming qualities of an HttpServer.
  * Pausing the subscription of the stream, pauses at the OS level.
- * 
+ *
  * * The [http_server](https://pub.dartlang.org/packages/http_server)
  * package on pub.dartlang.org contains a set of high-level classes that,
  * together with this class, makes it easy to provide content through HTTP
@@ -153,11 +153,13 @@ abstract class HttpStatus {
  */
 abstract class HttpServer implements Stream<HttpRequest> {
   /**
-   * Set and get the default value of the `Server` header for all responses
-   * generated by this [HttpServer]. By default, it's disabled.
+   * Get and set the default value of the `Server` header for all responses
+   * generated by this [HttpServer].
+   *
+   * If [serverHeader] is `null`, no `Server` header will be added to each
+   * response.
    *
-   * If the serverHeader is set to `null`, no default `Server` header will be
-   * added to each response.
+   * The default value is `null`.
    */
   String serverHeader;
 
@@ -987,7 +989,7 @@ abstract class HttpRequest implements Stream<List<int>> {
  * The server sends its response to the client by writing to the
  * HttpResponse object.
  *
- * ## Writing the response 
+ * ## Writing the response
  *
  * This class implements [IOSink].
  * After the header has been set up, the methods