made the crates/ide-assists/src/handlers/add_missing_impl_members.rs file tidy

Author: ponyii

crates/ide-assists/src/handlers/add_missing_impl_members.rs

@@ -1581,7 +1581,7 @@ mod m {
 
     impl Foo for S {
         fn bar(&self) {}
-    $0
+$0
     }
 }"#,
             r#"
@@ -1613,7 +1613,7 @@ mod m {
         fn baz(&self) {
             todo!()
         }
-    
+
     }
 }"#,
         );