Fixed warnings in HighPerformance unit tests

Author: Sergio0694

UnitTests/UnitTests.HighPerformance.Shared/Enumerables/Test_ReadOnlyRefEnumerable{T}.cs

@@ -5,13 +5,15 @@
 #if !WINDOWS_UWP
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using Microsoft.Toolkit.HighPerformance.Enumerables;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 
 namespace UnitTests.HighPerformance.Enumerables
 {
     [TestClass]
+    [SuppressMessage("StyleCop.CSharp.DocumentationRules", "SA1649", Justification = "Test class for generic type")]
     public class Test_ReadOnlyRefEnumerable
     {
         [TestCategory("ReadOnlyRefEnumerable")]

UnitTests/UnitTests.HighPerformance.Shared/Enumerables/Test_RefEnumerable{T}.cs

@@ -5,13 +5,15 @@
 #if !WINDOWS_UWP
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using Microsoft.Toolkit.HighPerformance.Enumerables;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 
 namespace UnitTests.HighPerformance.Enumerables
 {
     [TestClass]
+    [SuppressMessage("StyleCop.CSharp.DocumentationRules", "SA1649", Justification = "Test class for generic type")]
     public class Test_RefEnumerable
     {
         [TestCategory("RefEnumerable")]