Annotate tests.

Author: JohanLarsson

PropertyChangedAnalyzers.Test/INPC015PropertyIsRecursive/Valid.cs

@@ -16,7 +16,6 @@ public static void NotifyingProperty()
 namespace N
 {
     using System.ComponentModel;
-    using System.Runtime.CompilerServices;
 
     public class C : INotifyPropertyChanged
     {
@@ -59,9 +58,6 @@ public static void GetSetBackingFieldExpressionBodies()
             var code = @"
 namespace N
 {
-    using System.ComponentModel;
-    using System.Runtime.CompilerServices;
-
     public class C
     {
         private int p;
@@ -110,7 +106,7 @@ public class C1
 
     public class C2 : C1
     {
-        public int P
+        public override int P
         {
             get => base.P;
             set => base.P = value;
@@ -132,7 +128,7 @@ namespace N
 
     public class C : IReadOnlyList<int>
     {
-        private readonly List<int> ints;
+        private readonly List<int> ints = new();
         
         public int Count => ints.Count;
 

PropertyChangedAnalyzers.Test/INPC016NotifyAfterUpdate/Diagnostics.cs

@@ -1,4 +1,4 @@
-namespace PropertyChangedAnalyzers.Test.INPC016NotifyAfterUpdate
+namespace PropertyChangedAnalyzers.Test.INPC016NotifyAfterUpdate
 {
     using Gu.Roslyn.Asserts;
     using NUnit.Framework;
@@ -92,7 +92,6 @@ public static void OnPropertyChangedPropertyChangedEventArgsBeforeAssign()
 namespace N
 {
     using System.ComponentModel;
-    using System.Runtime.CompilerServices;
 
     public class C : INotifyPropertyChanged
     {
@@ -173,11 +172,11 @@ namespace N.Client
 {
     public class C : N.Core.ViewModelBase
     {
-        private string p2;
+        private string? p2;
 
         public string P1 => $""Hello {this.P2}"";
 
-        public string P2
+        public string? P2
         {
             get { return this.p2; }
             set