Miscellaneous typos and errors in en_US lang files

htdocs/adherents/admin/public.php

htdocs/langs/en_US/admin.lang

htdocs/langs/en_US/banks.lang

htdocs/langs/en_US/bills.lang

htdocs/langs/en_US/boxes.lang

htdocs/langs/en_US/commercial.lang

htdocs/langs/en_US/companies.lang

htdocs/langs/en_US/compta.lang

htdocs/langs/en_US/contracts.lang

htdocs/langs/en_US/cron.lang

htdocs/langs/en_US/donations.lang

htdocs/langs/en_US/errors.lang

htdocs/langs/en_US/holiday.lang

htdocs/langs/en_US/install.lang

htdocs/langs/en_US/interventions.lang

htdocs/langs/en_US/mailmanspip.lang

htdocs/langs/en_US/mails.lang

htdocs/langs/en_US/main.lang

htdocs/langs/en_US/members.lang

htdocs/langs/en_US/orders.lang