Show correct reason for mentioned mail and some minor changes in the text display

app/views/work_package_mailer/mentioned.html.erb

@@ -15,13 +15,13 @@
       <%= render layout: 'mailer/notification_row',
                  locals: {
                    work_package: @work_package,
-                   unique_reasons: [I18n.t(:'mail.work_packages.reason.mentioned')],
+                   unique_reasons: [:mentioned],
                    show_count: false
                  } do %>
         <table <%= placeholder_table_styles %>>
           <tr>
             <td style="color: #878787; line-height: 24px; font-size: 14px; white-space: normal;">
-                <%= @journal.notes.html_safe %>
+              <%= simple_format @journal.notes %>
             </td>
           </tr>
         </table>

app/views/work_package_mailer/mentioned.text.erb

@@ -8,6 +8,6 @@
 <%= "=" * (('# ' + @work_package.id.to_s + @work_package.subject).length + 4) %>
 
 <%= I18n.t(:label_comment_added) %>:
-<%= @journal.notes %>
+<%= strip_tags @journal.notes %>
 
 <%= "-" * 100 %>