Merge pull request #2006 from wpfcontrib/fixup-app-template-rel31

Add `ThemeInfoAttribute` to application project templates

packaging/Microsoft.Dotnet.Wpf.ProjectTemplates/content/WpfApplication-CSharp/AssemblyInfo.cs

+using System.Windows;
+
+[assembly:ThemeInfo(
+    ResourceDictionaryLocation.None, //where theme specific resource dictionaries are located
+                                     //(used if a resource is not found in the page,
+                                     // or application resource dictionaries)
+    ResourceDictionaryLocation.SourceAssembly //where the generic resource dictionary is located
+                                              //(used if a resource is not found in the page,
+                                              // app, or any theme specific resource dictionaries)
+)]

packaging/Microsoft.Dotnet.Wpf.ProjectTemplates/content/WpfApplication-VisualBasic/AssemblyInfo.vb

+Imports System.Windows
+
+'The ThemeInfo attribute describes where any theme specific and generic resource dictionaries can be found.
+'1st parameter: where theme specific resource dictionaries are located
+'(used if a resource is not found in the page,
+' or application resource dictionaries)
+
+'2nd parameter: where the generic resource dictionary is located
+'(used if a resource is not found in the page,
+'app, and any theme specific resource dictionaries)
+<Assembly: ThemeInfo(ResourceDictionaryLocation.None, ResourceDictionaryLocation.SourceAssembly)>