Clean up warnings in menu file

Author: niftynei

app/src/main/res/menu/context_single_private.xml

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <menu xmlns:android="http://schemas.android.com/apk/res/android" >
-    <item android:id="@+id/reply_to_private" android:title="Reply to Private Message"></item>
-    <item android:id="@+id/narrow_to_private" android:title="Narrow to this conversation"></item>
-    <item android:id="@+id/copy_message" android:title="Copy Message"></item>
-
+    <item android:id="@+id/reply_to_private" android:title="@string/reply_to_private_message" />
+    <item android:id="@+id/narrow_to_private" android:title="@string/narrow_to_this_conversation" />
+    <item android:id="@+id/copy_message" android:title="@string/copy_message" />
 </menu>

app/src/main/res/values/strings.xml

@@ -29,5 +29,8 @@
     <string name="loading_messages">Loading messages</string>
     <string name="sending_message">Sending</string>
     <string name="search">Search</string>
+    <string name="reply_to_private_message">Reply to Private Message</string>
+    <string name="narrow_to_this_conversation">Narrow to this conversation</string>
+    <string name="copy_message">Copy Message</string>
 
 </resources>