Switch string creation to String::new()?

[nzeh]

tree_child_code/tree_child/src/app/io.rs

Line 16 in a46acfc

let mut newick = String::from("");

I think I have String::from("") here because (I thought) there was a need to have a fully initialized string here. I doubt that this is actually the case, so String::new() would be more idiomatic.