T10694 brought in a nice inline html diff rendering for differential emails. It would be useful if that was brought over to diffusion in two places:

1. Inline comments in audit
2. Commit message emails

Reasons for wanting this:

• It is consistent. I was confused that the red/green html diff is only available in one place and not another
• We review code after it is committed, so being able to quickly read an email diff and see the changes is really helpful. Anything that makes reading those emails easier saves a lot of time.
• It is pretty :-)