example/ivy/android: remove prompt symbol

Now the user input is printed in bold, so it is obvious even with
out this dummy prompt-like symbol. This makes the output more like
the desktop version of Ivy tool.

Change-Id: I146685815ceb52aa5da6ddaa64f764e43839ffa9
Reviewed-on: https://go-review.googlesource.com/c/mobile/+/356733
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Trust: Cherry Mui <cherryyz@google.com>
diff --git a/example/ivy/android/app/src/main/java/org/golang/ivy/MainActivity.java b/example/ivy/android/app/src/main/java/org/golang/ivy/MainActivity.java
index d58d9c4..b7d5e06 100644
--- a/example/ivy/android/app/src/main/java/org/golang/ivy/MainActivity.java
+++ b/example/ivy/android/app/src/main/java/org/golang/ivy/MainActivity.java
@@ -43,7 +43,6 @@
 public class MainActivity extends AppCompatActivity {
     final String DEMO_SCRIPT = "demo.ivy";  // in assets directory.
     final String DEBUG_TAG = "Ivy";
-    final String PROMPT = "> ";
 
     private WebView mWebView;
     private EditText mEditText;
@@ -242,7 +241,7 @@
     private void callIvy() {
         String s = mEditText.getText().toString().trim();
         if (s != null && !s.isEmpty()) {
-            appendShowText(PROMPT + s, "expr");
+            appendShowText(s, "expr");
         }
         if (mDemo != null && s.trim().equals("quit")) {
             unloadDemo();