LogWrapper::<<(list) does not behave like LogWrapper::<<(string) used on each element of the list

Calling `info() << someList` should be identical to calling `info() << element` on each element of `someList`.

This is not the case because when used on a list, the string is concatenated with `\n` and the logging callback is called once. Instead, the logging  callback should be called for each line and we shouldn't assume anything on the "newline" character.
