i18n: Fix several untranslated texts and missing help tips

include/ajax.content.php

include/class.forms.php

...e/i18n/en_US/help/tips/knowledgebase.canned_response.yaml

include/i18n/en_US/help/tips/knowledgebase.category.yaml

include/i18n/en_US/help/tips/settings.ticket.yaml

include/staff/cannedresponse.inc.php

include/staff/cannedresponses.inc.php

include/staff/categories.inc.php

include/staff/directory.inc.php

include/staff/faq-categories.inc.php

include/staff/helptopic.inc.php

include/staff/orgs.inc.php

include/staff/settings-tickets.inc.php

include/staff/ticket-open.inc.php

scp/js/tips.js

scp/lists.php