chore: fix clippy

src/error.rs

@@ -1,4 +1,6 @@
-#[derive(thiserror::Error, Debug)]
+use thiserror::Error;
+
+#[derive(Error, Debug)]
 pub enum RuntimeError {
     #[error("Invalid character found")]
     UnexpectedChar,

src/main.rs

@@ -61,7 +61,7 @@ fn main() -> Result<(), Error> {
             Err(e) => eprintln!("Failed to initialize repository: {}", e),
         },
         Command::CatFile { hash } => match read_object(&path, &hash) {
-            Ok(mut obj) => println!("{}", obj.to_string()?),
+            Ok(mut obj) => println!("{}", obj.string()?),
             Err(e) => eprintln!("Failed to read object: {}", e),
         },
     }

src/object.rs

@@ -62,7 +62,7 @@ pub fn read_object(path: &Path, object: &str) -> Result<Object<impl BufRead>> {
 }
 
 impl<R: BufRead> Object<R> {
-    pub fn to_string(&mut self) -> Result<String> {
+    pub fn string(&mut self) -> Result<String> {
         let mut buf: Vec<u8> = Vec::new();
         let mut buf_hash: [u8; 20] = [0; 20];