Today I learned that GitHub has allows you to insert a one-line suggestion while conducting a pull request review. Click on the button circled in red, and you’ll get a
suggestion fenced code block, as shown.
Inside the code block is the current code; replace it with your proposed change. GitHub will present your suggestion in a nice diff format.
When the pull requester views your suggestion, they can accept the change with one click. Efficient!
Multiple-lines are not yet supported, according to this GitHub blog post it is a frequently requested feature.
h/t Jed and Raelyn