Docs: Fixing broken link in TtsEngine/_index.html

This change fixes a broken link in the index page for
development/samples/TtsEngine. RobotSpeakEngine needs to be renamed
to RobotSpeakTtsService.

Issue: 6032266
Change-Id: I2271ab43e866ff7d2f3b78cbe7d7035e1b4a794f
diff --git a/samples/TtsEngine/_index.html b/samples/TtsEngine/_index.html
index 07a54a9..85c3f22 100644
--- a/samples/TtsEngine/_index.html
+++ b/samples/TtsEngine/_index.html
@@ -4,7 +4,7 @@
 <p>The application includes a service and two activities:</p>
 <ul>
   <li><a
-    href="src/com/example/android/ttsengine/RobotSpeakEngine.html"><code>RobotSpeakEngine</code></a>,
+    href="src/com/example/android/ttsengine/RobotSpeakTtsService.html"><code>RobotSpeakTtsService</code></a>,
     a simple text to speech engine that converts sentences into audio by
     generating a square wave of a given frequency for each alphabet of a
     given language. Though this doesn't qualify as speech (except for robots)