Refactor link to new diff note rendering

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Merge branch 'faster-diff-rendering' into 'master'

Faster diff rendering

1. Dont render link in separate template but use helper instead
2. Don't build new object but just reuse variables

New note for diff is rendered per each diff line. Such simple improvements gives us 20..100% better performance depends on diff size