refactor: remove module prefixes from compression and digest engine functions

src/modes/diff.rs

@@ -133,7 +133,7 @@ pub fn mode_diff(
     ) {
         use std::io::BufWriter;
         let mut buffered_pipe_writer = BufWriter::new(pipe_writer_raw);
-        let engine = crate::compression_engine::get_compression_engine(compression_type)
+        let engine = get_compression_engine(compression_type)
             .expect("Unable to get compression engine");
         log::debug!("THREAD: Sending item to diff");
         engine