Add hint that file names are clickable

Author: chriskuehl

pypi_browser/templates/package_file.html

@@ -47,6 +47,7 @@ <h4>Package Metadata</h4>
     {% endif %}
 
     <h4>Package Files</h4>
+    <p class="small">Click a file name below to view its contents.</p>
     <div class="card bg-light mb-3">
         <div class="list-group list-group-flush">
             {% for entry in entries|sort(attribute="path") %}