improve wording of one-to-one-chat hint (#2165)

* improve wording of one-to-one-chat hint

at #2134 we shortend the hint shown for an empty group massively,
removing greylisting hints and the hint that the recipient can user other mua.

the result of that shortening is that the creation of a one-to-one chat
is now way too long :)

i suggest shorten the hint in a similar way,
not much would be left then, however, that is maybe not bad :)

* re-add the aspect that the recipient does not need Delta Chat

res/values/strings.xml

@@ -358,6 +358,8 @@
         <item quantity="other">%d new messages</item>
     </plurals>
     <string name="chat_no_messages_hint">Send message to %1$s:\n\n• It is okay if %2$s does not use Delta Chat.\n\n• Delivering the first message may take a while and may be unencrypted.</string>
+    <!-- The placeholder will be replaced by the name of the recipient in a one-to-one chat. -->
+    <string name="chat_new_one_to_one_hint">Send a message. It is okay if %1$s does not use Delta Chat.</string>
     <string name="chat_new_broadcast_hint">In a broadcast list, others will receive messages in their private chats with you.\n\nThe recipients will not be aware of each other.</string>
     <string name="chat_new_group_hint">Others will only see this group after you sent a first message.</string>
     <string name="chat_record_slide_to_cancel">Slide to cancel</string>

src/org/thoughtcrime/securesms/ConversationFragment.java

@@ -191,7 +191,7 @@ public class ConversationFragment extends MessageSelectorFragment
             noMessageTextView.setText(R.string.device_talk_explain);
         }
         else {
-            String message = getString(R.string.chat_no_messages_hint, dcChat.getName(), dcChat.getName());
+            String message = getString(R.string.chat_new_one_to_one_hint, dcChat.getName());
             noMessageTextView.setText(message);
         }
     }