Don't post process commit summary in templates (#6842)
* Don't post process commit summary in templates
Don't run summary through render/post process to avoid it generating
links and breaking certain views where the summary is already expected
to be a link to the commit. For consistancy, disable processing of
summary in all locations.
Fixes#6809
* Do process title on diff page
On second thought, the title is often the only place a pull request
number will exists so do process it on the individual diff page. This
fixes the list view and still gives easy access to the PR link