Mention WebTestClient in Gradle getting started example

See gh-654

Author: LichKing-lee

docs/src/docs/asciidoc/getting-started.adoc

@@ -172,9 +172,9 @@ the configuration are described in the following listings:
 	This will automatically configure the `snippets` attribute for use in your `.adoc`
 	files to point to `build/generated-snippets`. It will also allow you to use the
 	`operation` block macro.
-<3> Add a dependency on `spring-restdocs-mockmvc` in the `testCompile` configuration. If
-	you want to use REST Assured rather than MockMvc, add a dependency on
-	`spring-restdocs-restassured` instead.
+<3> Add a dependency on `spring-restdocs-mockmvc` in the `testCompile` configuration. If you want to use
+	`WebTestClient` or REST Assured rather than MockMvc, add a dependency on
+	`spring-restdocs-webtestclient` or `spring-restdocs-restassured` respectively instead.
 <4> Configure a property to define the output location for generated snippets.
 <5> Configure the `test` task to add the snippets directory as an output.
 <6> Configure the `asciidoctor` task