bulk code format fix (#8707)

samples/sample_flexbuffers.rs

@@ -135,10 +135,7 @@ fn main() {
 
     // Analogously, the `index` method is the safe version of `idx`.
     assert!(read_monster.index("hp").is_ok());
-    assert_eq!(
-        read_monster.index("foo").unwrap_err(),
-        ReaderError::KeyNotFound
-    );
+    assert_eq!(read_monster.index("foo").unwrap_err(), ReaderError::KeyNotFound);
 
     // Maps can also be indexed by usize. They're stored by key so `coins` are the first element.
     let monster_coins = read_monster.idx(0);