Tweak dune file formatting: avoid pure vertical layout when formatting wrapped lists

[nojb]

Fixes #10860

The effect of the change is illustrated in the tests.

cc @Khady

[rgrinberg]

LGTM. Changes entry please

[Khady]

Thanks! It would definitely help with run. I don't have a real opinion about the impact on other wrapped lists. From the diff it generally looks good. Two points where it could look worse are modules and libraries where it can be useful to have things kept in a alphabetical order to ease reading. I tend to think that the horizontal layout would be fine anyway.

[nojb]

I don't have a real opinion about the impact on other wrapped lists.

Unfortunately, the formatter works at the level of s-expressions; so we don't really know the difference between "run" and other lists, so using different formatting for different types of wrapped lists is not straightforward at the moment.

[Khady]

thanks :)