At the moment the formatter leaves string literals alone however long they are, so a single error message can push a line well past the limit. I would like it to split them at word boundaries using implicit concatenation.
The obvious risk is changing the meaning of code that relies on the exact layout, but I cannot think of a case where adjacent literals behave differently from one long literal.
Byte strings and f-strings would need care, and splitting inside an escape sequence would be a nasty bug to ship. I would rather see it behind an option first, so that people can try it on real code bases.
An option seems fair. I will write up the escape sequence cases in the proposal so the behaviour is pinned down before anyone implements it.
