Add 'InternalsVisibleTo' for code fixers

Author: Sergio0694

components/DependencyPropertyGenerator/CommunityToolkit.DependencyPropertyGenerator.SourceGenerators/CommunityToolkit.DependencyPropertyGenerator.SourceGenerators.csproj

@@ -9,6 +9,11 @@
     <NoWarn>$(NoWarn);IDE0130</NoWarn>
   </PropertyGroup>
 
+  <!-- Allow the code fixers to access internal APIs (such a diagnostic IDs) -->
+  <ItemGroup>
+    <InternalsVisibleTo Include="CommunityToolkit.DependencyPropertyGenerator.CodeFixers"/>
+  </ItemGroup>
+
   <ItemGroup>
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.12.0" PrivateAssets="all" />
     <PackageReference Include="PolySharp" Version="1.15.0" PrivateAssets="all" />