fix typos of source comments at Project model

git-svn-id: http://svn.redmine.org/redmine/trunk@13057 e93f8b46-1217-0410-a6f0-8f06a7374b81
fix typos of source comments at WikiContent model

git-svn-id: http://svn.redmine.org/redmine/trunk@13058 e93f8b46-1217-0410-a6f0-8f06a7374b81
fix typos of source comments at acts_as_event.rb

git-svn-id: http://svn.redmine.org/redmine/trunk@13059 e93f8b46-1217-0410-a6f0-8f06a7374b81