Preview route tooling improvements:

1. Install .NET 8 SDK from https://github.com/dotnet/installer/blob/main/README.md#table
2. Open app in Visual Studio
3. Toggle app version in csproj between 7.0 and 8.0 to turn tooling on and off.

Route tooling features:

• Route syntax colorization
• Brace match highlighting
• Route parameter highlighting
• Route completion:
  • Constraints
  • Route parameter name from delegate argument name
  • Delegate argument name from route parameter name
• Code fixer to add delegate argument from parameter
• Route syntax analyzer