[#1999] Add additional explanation to show a max of 5 MB upload limit

akvo/templates/myrsr/project_editor/section_9.html

@@ -12,7 +12,11 @@
             </div>
         </div>
         <div class="formBlock hidden">
-            <p class="help-block hidden" id="step-9-helptext">{% trans 'You can add any additional supporting documents to your project or links to external websites here. This could be in the form of annual reports, baseline surveys, contextual information or any other report that can help users understand more about the project’s activities.' %}</p>
+            <p class="help-block hidden" id="step-9-helptext">
+                {% trans 'You can add any additional supporting documents to your project or links to external websites here.' %}
+                {% trans 'This could be in the form of annual reports, baseline surveys, contextual information or any other report that can help users understand more about the project’s activities.' %}
+                {% trans 'Note that the size of documents should be smaller than 5 MB.' %}
+            </p>
             <form role="form">
                 <div class="related-object-container {{ validations|mandatory_or_hidden:"rsr_link" }}">
                     <h5>{% trans 'Links' %}</h5>