Make KeysCollection.Contains methods public. (dotnet#76319)

Author: eiriktsarpalis

src/libraries/System.Collections/ref/System.Collections.cs

@@ -209,7 +209,7 @@ public void CopyTo(TKey[] array, int index) { }
             public System.Collections.Generic.SortedDictionary<TKey, TValue>.KeyCollection.Enumerator GetEnumerator() { throw null; }
             void System.Collections.Generic.ICollection<TKey>.Add(TKey item) { }
             void System.Collections.Generic.ICollection<TKey>.Clear() { }
-            bool System.Collections.Generic.ICollection<TKey>.Contains(TKey item) { throw null; }
+            public bool Contains(TKey item) { throw null; }
             bool System.Collections.Generic.ICollection<TKey>.Remove(TKey item) { throw null; }
             System.Collections.Generic.IEnumerator<TKey> System.Collections.Generic.IEnumerable<TKey>.GetEnumerator() { throw null; }
             void System.Collections.ICollection.CopyTo(System.Array array, int index) { }
@@ -500,7 +500,7 @@ public void CopyTo(TKey[] array, int index) { }
             public System.Collections.Generic.Dictionary<TKey, TValue>.KeyCollection.Enumerator GetEnumerator() { throw null; }
             void System.Collections.Generic.ICollection<TKey>.Add(TKey item) { }
             void System.Collections.Generic.ICollection<TKey>.Clear() { }
-            bool System.Collections.Generic.ICollection<TKey>.Contains(TKey item) { throw null; }
+            public bool Contains(TKey item) { throw null; }
             bool System.Collections.Generic.ICollection<TKey>.Remove(TKey item) { throw null; }
             System.Collections.Generic.IEnumerator<TKey> System.Collections.Generic.IEnumerable<TKey>.GetEnumerator() { throw null; }
             void System.Collections.ICollection.CopyTo(System.Array array, int index) { }

src/libraries/System.Collections/src/System/Collections/Generic/SortedDictionary.cs

@@ -637,7 +637,7 @@ void ICollection<TKey>.Clear()
                 throw new NotSupportedException(SR.NotSupported_KeyCollectionSet);
             }
 
-            bool ICollection<TKey>.Contains(TKey item)
+            public bool Contains(TKey item)
             {
                 return _dictionary.ContainsKey(item);
             }

src/libraries/System.Private.CoreLib/src/System/Collections/Generic/Dictionary.cs

@@ -1504,7 +1504,7 @@ void ICollection<TKey>.Add(TKey item) =>
             void ICollection<TKey>.Clear() =>
                 ThrowHelper.ThrowNotSupportedException(ExceptionResource.NotSupported_KeyCollectionSet);
 
-            bool ICollection<TKey>.Contains(TKey item) =>
+            public bool Contains(TKey item) =>
                 _dictionary.ContainsKey(item);
 
             bool ICollection<TKey>.Remove(TKey item)

src/libraries/System.Private.CoreLib/src/System/Collections/ObjectModel/ReadOnlyDictionary.cs

@@ -264,7 +264,7 @@ void ICollection<TKey>.Clear()
                 throw new NotSupportedException(SR.NotSupported_ReadOnlyCollection);
             }
 
-            bool ICollection<TKey>.Contains(TKey item)
+            public bool Contains(TKey item)
             {
                 return _collection.Contains(item);
             }

src/libraries/System.Runtime/ref/System.Runtime.cs

@@ -7608,7 +7608,7 @@ public void CopyTo(TKey[] array, int arrayIndex) { }
             public System.Collections.Generic.IEnumerator<TKey> GetEnumerator() { throw null; }
             void System.Collections.Generic.ICollection<TKey>.Add(TKey item) { }
             void System.Collections.Generic.ICollection<TKey>.Clear() { }
-            bool System.Collections.Generic.ICollection<TKey>.Contains(TKey item) { throw null; }
+            public bool Contains(TKey item) { throw null; }
             bool System.Collections.Generic.ICollection<TKey>.Remove(TKey item) { throw null; }
             void System.Collections.ICollection.CopyTo(System.Array array, int index) { }
             System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() { throw null; }