feat(span): add `Atom::from_strs_array_in` method (#11261)
Add `Atom::from_strs_array_in` method, to complement `String::from_strs_array_in`. In many places we were using `String::from_strs_array_in` only as a means to get an `Atom`. Cut out the middleman!
This prepares the way for #11260, and getting rid of `String` entirely.