Update SmsMessage.FORMAT_ Javadocs.

Change-Id: Ie8c5ed4593763d354afa49561be08e620ea95546
Fixes: 70336453
Test: None, trivial doc update
diff --git a/telephony/java/android/telephony/SmsMessage.java b/telephony/java/android/telephony/SmsMessage.java
index a5d67c6..68c1986 100644
--- a/telephony/java/android/telephony/SmsMessage.java
+++ b/telephony/java/android/telephony/SmsMessage.java
@@ -19,6 +19,7 @@
 import static android.telephony.TelephonyManager.PHONE_TYPE_CDMA;
 
 import android.annotation.StringDef;
+import android.app.PendingIntent;
 import android.content.res.Resources;
 import android.os.Binder;
 import android.text.TextUtils;
@@ -89,11 +90,13 @@
 
     /**
      * Indicates a 3GPP format SMS message.
+     * @see SmsManager#injectSmsPdu(byte[], String, PendingIntent)
      */
     public static final String FORMAT_3GPP = "3gpp";
 
     /**
      * Indicates a 3GPP2 format SMS message.
+     * @see SmsManager#injectSmsPdu(byte[], String, PendingIntent)
      */
     public static final String FORMAT_3GPP2 = "3gpp2";