Remove GFM from titles

Remove markdown rendering from titles in a list. It doesn't make sense to render markdown with links to issues, etc in a list because it disjoints the link. For example 'This merge request fixes #1' will result in 'This merge request fixes' being a link to the merge request and '#1' is a link to issue #1. 

This change makes sense for merge request, issue and commit lists. For merge requests and issues markdown will continue to be rendered when the merge request/issue is viewed.