Fix formatting in CONTRIBUTING.md.
Fix formatting in CONTRIBUTING.md.

tejasbubane/rubocop,bbatsov/rubocop,tdeo/rubocop,tdeo/rubocop,rrosenblum/rubocop,bbatsov/rubocop,tejasbubane/rubocop,rrosenblum/rubocop,maxjacobson/rubocop,tejasbubane/rubocop,maxjacobson/rubocop,maxjacobson/rubocop,tdeo/rubocop,rrosenblum/rubocop