cleanup

Author: pwelter34

src/Equatable.Comparers/DictionaryEqualityComparer.cs

@@ -47,7 +47,7 @@ public bool Equals(IDictionary<TKey, TValue>? x, IDictionary<TKey, TValue>? y)
         if (ReferenceEquals(x, y))
             return true;
 
-        if (x == null || y == null)
+        if (x is null || y is null)
             return false;
 
         if (x.Count != y.Count)

src/Equatable.Comparers/HashSetEqualityComparer.cs

@@ -37,7 +37,7 @@ public bool Equals(IEnumerable<TValue>? x, IEnumerable<TValue>? y)
         if (ReferenceEquals(x, y))
             return true;
 
-        if (x == null || y == null)
+        if (x is null || y is null)
             return false;
 
         if (x is ISet<TValue> xSet)

src/Equatable.Comparers/SequenceEqualityComparer.cs

@@ -37,7 +37,7 @@ public bool Equals(IEnumerable<TValue>? x, IEnumerable<TValue>? y)
         if (ReferenceEquals(x, y))
             return true;
 
-        if (x == null || y == null)
+        if (x is null || y is null)
             return false;
 
         return x.SequenceEqual(y, Comparer);