img markup should have alt attributes

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@31718 20353a03-c40f-0410-a6d1-a30d3c3de9de

bt5/erp5_web/SkinTemplateItem/portal_skins/erp5_web_widget_library/WebSection_viewToolbarWidget.xml

@@ -238,7 +238,7 @@
             <button id="clone_action_button" \n
                     title=\'Clone &amp; Edit\'\n
                     name="Base_cloneContent:method">\n
-              <img src="admin_toolbox_clone_document.png" id="clone_action_icon"\n
+              <img src="admin_toolbox_clone_document.png" id="clone_action_icon" alt="clone action icon"\n
                    tal:attributes="src string:$portal_url/admin_toolbox_clone_document.png" />\n
               <span id="duplicate_document_action">Clone &amp; Edit</span>\n
             </button>\n

bt5/erp5_web/SkinTemplateItem/portal_skins/erp5_web_widget_library/admin_toolbox.xml

@@ -167,7 +167,7 @@
             <button id="clone_action_button" \n
                     title=\'Clone &amp; Edit\'\n
                     name="Base_cloneContent:method">\n
-              <img src="admin_toolbox_clone_document.png" id="clone_action_icon"\n
+              <img src="admin_toolbox_clone_document.png" id="clone_action_icon" alt="clone action icon"\n
                    tal:attributes="src string:$portal_url/admin_toolbox_clone_document.png" />\n
               <span id="duplicate_document_action">Clone &amp; Edit</span>\n
             </button>\n

bt5/erp5_web/bt/revision

-888
+889
\ No newline at end of file