ruby/www.ruby-lang.org — pull request #411 by sgharms (2013-12-02 15:14:29+00:00)
Title: Update about/index.md: comma to colon

I believe that the correct punctuation for using a definition is a colon, not a comma. The description is in apposition (both functioning as nominative subjects) to the term and seems to suggest an appositive use.