The multi-line code suggestions feature is now generally available to all GitHub users.
With multi-line suggestions you can suggest a specific change to multiple lines of code when reviewing a pull request. To select a multi-line code block, either:
- click and hold to the right of a line number, drag and then release the mouse when you’ve reached the last line of the desired selection; or
- click on a line number, hold
Shift, click on a second line number and click the "+" button to the right of the second line number.
Once you've selected the code block, click the diff icon and edit the text within the suggestion block.