[hgreview] Automatically insert review link for Noissue commits

[trev]

Background

If a commit doesn't reference an issue it is supposed to include a link to the review. However, this requires amending the commit after submitting the review and is frequently forgotten.

What to change

hg review should check the commit title after creating a review with -c parameter. If no issue is referenced it should amend the commit and add \n\nReview: https://... to the description.