style: fix a cargo fmt check

src/write.rs

@@ -1320,10 +1320,7 @@ impl<W: Write + Seek> ZipWriter<W> {
     }
 
     fn index_by_name(&self, name: &str) -> ZipResult<usize> {
-        self
-            .files
-            .get_index_of(name)
-            .ok_or(ZipError::FileNotFound)
+        self.files.get_index_of(name).ok_or(ZipError::FileNotFound)
     }
 
     /// Adds another entry to the central directory referring to the same content as an existing