Add description to how drafts and registrations are sorted (#1204)

## Purpose
- Let users know that registrations and drafts are sorted by date modified

## Summary of Changes
- Add a div with explanation to my-registrations page template

## Side Effects
- Should be none.

## QA Notes
- There should be a little bit of text on the my registrations page that says how drafts and registrations are submitted. The text is the same for both tabs

Author: futa-ikeda

lib/registries/addon/my-registrations/styles.scss

@@ -52,3 +52,9 @@
         }
     }
 }
+
+.SortDescription {
+    text-align: right;
+    margin-top: 10px;
+    margin-right: 15px;
+}

lib/registries/addon/my-registrations/template.hbs

@@ -19,6 +19,9 @@
                     @activeId={{this.tab}}
                     as |tab|
                 >
+                    <div local-class='SortDescription'>
+                        {{t 'registries.my_registrations.sorted'}}
+                    </div>
                     <tab.pane
                         local-class='Tab'
                         @title={{t 'registries.my_registrations.drafts'}}

translations/en-us.yml

@@ -1138,6 +1138,7 @@ registries:
         header: 'My Registrations'
         drafts: 'Drafts'
         submitted: 'Submitted'
+        sorted: 'Sorted by last updated'
     registration_metadata:
         add_description: 'Add description'
         add_contributors: