mod rename_section {    use std::{borrow::Cow, convert::TryFrom};     use git_config::{file::rename_section, parse::section};     #[test]    fn section_renaming_validates_new_name() {        let mut file = git_config::File::try_from("[core] a = b").unwrap();        assert!(matches!(            file.rename_section("core", None, "new_core", None),            Err(rename_section::Error::Section(section::header::Error::InvalidName))        ));         assert!(matches!(            file.rename_section("core", None, "new-core", Cow::from("a\nb")),            Err(rename_section::Error::Section(                section::header::Error::InvalidSubSection            ))        ));    }}