Function rustdoc::html::format::href_relative_parts

pub(crate) fn href_relative_parts(
    fqp: &[String], 
    relative_to_fqp: &[String]
) -> UrlPartsBuilder

Both paths should only be modules. This is because modules get their own directories; that is, std::vec and std::vec::Vec will both need ../iter/trait.Iterator.html to get at the iterator trait.