Remove unused function

Author: Vinh Tran

src/driver.rs

@@ -171,14 +171,6 @@ fn display_help() {
     println!("{}", help_message());
 }
 
-fn read_lines<P>(filename: P) -> io::Result<io::Lines<io::BufReader<File>>>
-where
-    P: AsRef<Path>,
-{
-    let file = File::open(filename)?;
-    Ok(io::BufReader::new(file).lines())
-}
-
 const BUG_REPORT_URL: &str = "https://github.com/rust-lang/rust-clippy/issues/new?template=ice.yml";
 
 #[allow(clippy::too_many_lines)]