add hint about tag usage

customize.dist/translations/messages.js

@@ -160,7 +160,9 @@ define(function () {
     out.or = 'or';
 
     out.tags_title = "Tags";
-    out.tags_add = "Update this pad's tags";
+    out.tags_add = "Update this page's tags";
+    out.tags_searchHint = "Find files by their tags by searching in your CryptDrive";
+
     out.tags_duplicate = "Duplicate tag: {0}";
 
     out.slideOptionsText = "Options";

www/common/common-interface.js

@@ -177,7 +177,10 @@ define([
         var input = dialog.textInput();
 
         var tagger = dialog.frame([
-            dialog.message(Messages.tags_add),
+            dialog.message([
+                Messages.tags_add,
+                h('p', Messages.tags_searchHint)
+            ]),
             input,
             dialog.nav(),
         ]);