I don't even know if it's supported to have a lint replacement-text have a newline in it, but it seems to work fine. The only problem is the reporting is off:
(If you mouse over the second added line, you can see it's a bunch of spaces.)
The actual replacement we are doing is '' -> '\n ', right before the closing >. And indeed when we actually apply the fix, it shows this:
But in the initial lint error display, it shows the closing > on the first + line, when it should be at the end of the second.