docs(glossary): add XCode definition
docs(glossary): add XCode definition

Related: https://github.com/driftyco/ionic2/issues/543

ionic-team/ionic-site,ionic-team/ionic-site,driftyco/ionic-site,driftyco/ionic-site,driftyco/ionic-site,ionic-team/ionic-site,driftyco/ionic-site,ionic-team/ionic-site,driftyco/ionic-site