Inline .ToSet() method.

I initially added .ToSet() to EnumerableExtensions.cs, not realizing it was a paket file and thus not directly editable in this repo.

Author: bberger

src/CommandLine/Core/TokenPartitioner.cs

@@ -11,20 +11,16 @@ namespace CommandLine.Core
     static class TokenPartitioner
     {
         public static
-            Tuple<
-                IEnumerable<KeyValuePair<string, IEnumerable<string>>>, // options
-                IEnumerable<string>,                                    // values
-                IEnumerable<Token>                                      // errors
-            > Partition(
+            Tuple<IEnumerable<KeyValuePair<string, IEnumerable<string>>>, IEnumerable<string>, IEnumerable<Token>> Partition(
                 IEnumerable<Token> tokens,
                 Func<string, Maybe<TypeDescriptor>> typeLookup)
         {
             IEqualityComparer<Token> tokenComparer = ReferenceEqualityComparer.Default;
 
             var tokenList = tokens.Memorize();
-            var switches = Switch.Partition(tokenList, typeLookup).ToSet(tokenComparer);
-            var scalars = Scalar.Partition(tokenList, typeLookup).ToSet(tokenComparer);
-            var sequences = Sequence.Partition(tokenList, typeLookup).ToSet(tokenComparer);
+            var switches = new HashSet<Token>(Switch.Partition(tokenList, typeLookup), tokenComparer);
+            var scalars = new HashSet<Token>(Scalar.Partition(tokenList, typeLookup), tokenComparer);
+            var sequences = new HashSet<Token>(Sequence.Partition(tokenList, typeLookup), tokenComparer);
             var nonOptions = tokenList
                 .Where(t => !switches.Contains(t))
                 .Where(t => !scalars.Contains(t))