[WO-982] Add placeholder to writer

src/tpl/write.html

@@ -72,7 +72,7 @@
       </ul>
     </header>
 
-    <textarea class="write__body" ng-model="body" spellcheck="true" wo-focus-me="state.lightbox === 'write' && writerTitle === 'Reply'" tabindex="3"></textarea>
+    <textarea class="write__body" ng-model="body" spellcheck="true" wo-focus-me="state.lightbox === 'write' && writerTitle === 'Reply'" tabindex="3" placeholder="Compose email"></textarea>
   </div><!--/write-->
 
   <footer class="lightbox__controls">