templates: Clean up wording around topic moves.

This switches us to cleaner, simpler labels for moving topics; while
also avoiding claiming that we're only allowing moving topics to other
streams.

static/templates/move_topic_to_stream.hbs

@@ -1,10 +1,10 @@
 <div id="move_topic_modal" class="modal modal-bg hide fade new-style" tabindex="-1" role="dialog" aria-labelledby="move_topic_modal_label" aria-hidden="true">
     <div class="modal-header">
         <button type="button" class="close" data-dismiss="modal" aria-label="{{t 'Close' }}"><span aria-hidden="true">&times;</span></button>
-        <h3 id="move_topic_modal_label">{{t "Move a topic to stream" }} </h3>
+        <h3 id="move_topic_modal_label">{{t "Move topic" }} </h3>
     </div>
     <div class="modal-body">
-        <p>{{#tr this}}Do you want to move all messages in <strong>__topic_name__</strong> to another stream?{{/tr}}</p>
+        <p>{{#tr this}}Move all messages in <strong>__topic_name__</strong>{{/tr}} to:</p>
         <form id="move_topic_form">
             <div id="topic_stream_edit_form_error" class="alert">
                 <span class="send-status-close">&times;</span>

static/templates/topic_sidebar_actions.hbs

@@ -55,7 +55,7 @@
     <li>
         <a class="sidebar-popover-move-topic-messages" data-stream-id="{{ stream_id }}" data-topic-name="{{ topic_name }}">
             <i class="fa fa-arrows" aria-hidden="true"></i>
-            {{t "Move topic to another stream"}}
+            {{t "Move topic"}}
         </a>
     </li>
     {{/if}}

templates/zerver/help/rename-a-topic.md

@@ -43,7 +43,7 @@ another.
 
 {!stream-actions.md!}
 
-1. Select **Move <topic name\> to another stream**.
+1. Select **Move topic**.
 
 1. Select the destination stream for the topic from the streams dropdown list.