Update xml docs for 2.4 release

Author: natemcmaster

Directory.Build.props

@@ -51,4 +51,7 @@
     <PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.0-preview.2" PrivateAssets="all" />
   </ItemGroup>
 
+  <Import Project="$(MSBuildProjectDirectory)/releasenotes.props"
+          Condition="Exists('$(MSBuildProjectDirectory)/releasenotes.props')" />
+
 </Project>

src/CommandLineUtils/CommandLineApplication.cs

@@ -271,14 +271,16 @@ public CommandOption? OptionHelp
         /// This property has been marked as obsolete and will be removed in a future version.
         /// The recommended replacement for setting this property is <see cref="OnExecute(Func{int})" />
         /// and for invoking this property is <see cref="Execute(string[])" />.
+        /// See https://github.com/natemcmaster/CommandLineUtils/issues/275 for details.
         /// </para>
         /// <para>
         /// The action to call when this command is matched and <see cref="IsShowingInformation"/> is <c>false</c>.
         /// </para>
         /// </summary>
         [Obsolete("This property has been marked as obsolete and will be removed in a future version. " +
             "The recommended replacement for setting this property is OnExecute(Func<int>) " +
-            "and for invoking this property is Execute(string[] args).")]
+            "and for invoking this property is Execute(string[] args). " +
+            "See https://github.com/natemcmaster/CommandLineUtils/issues/275 for details.")]
         [EditorBrowsable(EditorBrowsableState.Never)]
         public Func<int> Invoke
         {
@@ -687,14 +689,16 @@ public void OnExecute(Func<int> invoke)
         /// <para>
         /// This method is obsolete and will be removed in a future version.
         /// The recommended alternative is <see cref="OnExecuteAsync" />.
+        /// See https://github.com/natemcmaster/CommandLineUtils/issues/275 for details.
         /// </para>
         /// <para>
         /// Defines an asynchronous callback.
         /// </para>
         /// </summary>
         /// <param name="invoke"></param>
         [Obsolete("This method is obsolete and will be removed in a future version. " +
-                  "The recommended replacement is .OnExecuteAsync()")]
+                  "The recommended replacement is .OnExecuteAsync(). " +
+                  "See https://github.com/natemcmaster/CommandLineUtils/issues/275 for details.")]
         [EditorBrowsable(EditorBrowsableState.Never)]
         public void OnExecute(Func<Task<int>> invoke) => OnExecuteAsync(_ => invoke());
 

src/CommandLineUtils/CommandLineApplicationExtensions.cs

@@ -100,6 +100,7 @@ public static CommandOption VerboseOption(this CommandLineApplication app, strin
         /// <para>
         /// This method is obsolete and will be removed in a future version.
         /// The recommended alternative is <see cref="OnExecuteAsync" />.
+        /// See https://github.com/natemcmaster/CommandLineUtils/issues/275 for details.
         /// </para>
         /// <para>
         /// Sets an async handler with a return code of <c>0</c>.
@@ -108,7 +109,8 @@ public static CommandOption VerboseOption(this CommandLineApplication app, strin
         /// <param name="app"></param>
         /// <param name="action">An asynchronous action to invoke when the ocmmand is selected..</param>
         [Obsolete("This method is obsolete and will be removed in a future version. " +
-                  "The recommended replacement is .OnExecuteAsync()")]
+                  "The recommended replacement is .OnExecuteAsync(). " +
+                  "See https://github.com/natemcmaster/CommandLineUtils/issues/275 for details.")]
         [EditorBrowsable(EditorBrowsableState.Never)]
         public static void OnExecute(this CommandLineApplication app, Func<Task> action)
         {

src/CommandLineUtils/McMaster.Extensions.CommandLineUtils.csproj

@@ -1,7 +1,5 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
-  <Import Project="releasenotes.props" />
-
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;netstandard1.6;net45</TargetFrameworks>
     <!--