fix cargo clippy warning and error

src/options/vars.rs

@@ -148,6 +148,5 @@ impl MockVars {
             "NO_COLOR" => self.no_colors = value.clone(),
             _ => (),
         };
-        ()
     }
 }

src/output/render/groups.rs

@@ -180,7 +180,7 @@ pub mod test {
                 GroupFormat::Regular,
                 file_user
             )
-        )
+        );
     }
 
     #[test]
@@ -203,7 +203,7 @@ pub mod test {
                 GroupFormat::Regular,
                 file_user
             )
-        )
+        );
     }
 
     #[test]

src/output/time.rs

@@ -158,7 +158,7 @@ mod test {
         let max_month_width = 4;
         let month = "1\u{2F49}"; // 1月
         let padding = short_month_padding(max_month_width, month);
-        let final_str = format!("{:<width$}", month, width = padding);
+        let final_str = format!("{month:<padding$}");
         assert_eq!(max_month_width, UnicodeWidthStr::width(final_str.as_str()));
     }