C# cleanup - assorted nits

csharp/src/ProtocolBuffers/Collections/RepeatedField.cs

@@ -44,9 +44,9 @@ namespace Google.Protobuf.Collections
     public sealed class RepeatedField<T> : IList<T>, IList, IDeepCloneable<RepeatedField<T>>, IEquatable<RepeatedField<T>>, IFreezable
     {
         private static readonly T[] EmptyArray = new T[0];
+        private const int MinArraySize = 8;
 
         private bool frozen;
-        private const int MinArraySize = 8;
         private T[] array = EmptyArray;
         private int count = 0;
 
@@ -259,7 +259,6 @@ namespace Google.Protobuf.Collections
 
         public int Count { get { return count; } }
 
-        // TODO(jonskeet): If we implement freezing, make this reflect it.
         public bool IsReadOnly { get { return IsFrozen; } }
 
         public void Add(RepeatedField<T> values)

csharp/src/ProtocolBuffers/FrameworkPortability.cs

@@ -40,6 +40,7 @@ namespace Google.Protobuf
     /// </summary>
     internal static class FrameworkPortability
     {
+        // TODO(jtattermusch): is this still a thing?
         // The value of RegexOptions.Compiled is 8. We can test for the presence at
         // execution time using Enum.IsDefined, so a single build will do the right thing
         // on each platform.

csharp/src/ProtocolBuffers/InvalidProtocolBufferException.cs

@@ -79,12 +79,6 @@ namespace Google.Protobuf
                 "Protocol message end-group tag did not match expected tag.");
         }
 
-        internal static InvalidProtocolBufferException InvalidWireType()
-        {
-            return new InvalidProtocolBufferException(
-                "Protocol message tag had invalid wire type.");
-        }
-
         internal static InvalidProtocolBufferException RecursionLimitExceeded()
         {
             return new InvalidProtocolBufferException(

csharp/src/ProtocolBuffers/ProtocolBuffers.csproj

@@ -111,7 +111,6 @@
   <ItemGroup>
     <None Include="Google.Protobuf.nuspec" />
   </ItemGroup>
-  <ItemGroup />
   <Import Project="$(MSBuildExtensionsPath32)\Microsoft\Portable\$(TargetFrameworkVersion)\Microsoft.Portable.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.

csharp/src/ProtocolBuffers/Reflection/IFieldAccessor.cs

@@ -42,7 +42,7 @@ namespace Google.Protobuf.Reflection
         /// </summary>
         FieldDescriptor Descriptor { get; }
 
-        // TODO: Should the argument type for these messages by IReflectedMessage?
+        // TODO: Should the argument type for these messages be IReflectedMessage?
 
         /// <summary>
         /// Clears the field in the specified message. (For repeated fields,