Fix for "%ss" being used as plural form on item pickup

This should fix #10126 causing i18n issues. It now uses the items "display_name()" function to show it's singular or plural form. I also reverted m_info being used on item pickup, as I shouldn't abuse that lovely blue text!
Well it wasn't ORIGINALLY m_info, that was a change I made with the last patch. However, I shouldn't be so angsty to change stuff just for my taste, bad habit of mine. (Compulsive person here).