Apply suggestions from code review

Co-authored-by: Josh Stone <cuviper@gmail.com>

Author: rouge8

src/map.rs

@@ -1342,7 +1342,7 @@ where
     }
 }
 
-#[cfg(all(rustc_1_51))]
+#[cfg(rustc_1_51)]
 impl<K, V, const N: usize> From<[(K, V); N]> for IndexMap<K, V, RandomState>
 where
     K: Hash + Eq,
@@ -1857,7 +1857,7 @@ mod tests {
     }
 
     #[test]
-    #[cfg(all(rustc_1_51))]
+    #[cfg(rustc_1_51)]
     fn from_array() {
         let map = IndexMap::from([(1, 2), (3, 4)]);
         let mut expected = IndexMap::new();

src/set.rs

@@ -840,7 +840,7 @@ where
     }
 }
 
-#[cfg(all(rustc_1_51))]
+#[cfg(rustc_1_51)]
 impl<T, const N: usize> From<[T; N]> for IndexSet<T, RandomState>
 where
     T: Eq + Hash,
@@ -1728,7 +1728,7 @@ mod tests {
     }
 
     #[test]
-    #[cfg(all(rustc_1_51))]
+    #[cfg(rustc_1_51)]
     fn from_array() {
         let set1 = IndexSet::from([1, 2, 3, 4]);
         let set2: IndexSet<_> = [1, 2, 3, 4].into();