csx syntax highlighting does not work correctly when `using` block on top level.

[itn3000]

Environment data

dotnet --info output:

.NET Core SDK (global.json を反映):
 Version:   2.1.300
 Commit:    adab45bf0c

ランタイム環境:
 OS Name:     Windows
 OS Version:  6.3.9600
 OS Platform: Windows
 RID:         win81-x64
 Base Path:   C:\Program Files\dotnet\sdk\2.1.300\

Host (useful for support):
  Version: 2.1.0
  Commit:  caa7b7e2ba

.NET Core SDKs installed:
  1.0.0-preview2-003118 [C:\Program Files\dotnet\sdk]
  1.0.0-preview2-003121 [C:\Program Files\dotnet\sdk]
  1.0.0-preview2-003131 [C:\Program Files\dotnet\sdk]
  1.0.0-preview2-003133 [C:\Program Files\dotnet\sdk]
  1.0.0-preview2-003156 [C:\Program Files\dotnet\sdk]
  1.0.0-preview2-1-003177 [C:\Program Files\dotnet\sdk]
  1.0.4 [C:\Program Files\dotnet\sdk]
  1.1.0 [C:\Program Files\dotnet\sdk]
  2.0.0-preview1-005977 [C:\Program Files\dotnet\sdk]
  2.0.0 [C:\Program Files\dotnet\sdk]
  2.0.2 [C:\Program Files\dotnet\sdk]
  2.1.2 [C:\Program Files\dotnet\sdk]
  2.1.3 [C:\Program Files\dotnet\sdk]
  2.1.4 [C:\Program Files\dotnet\sdk]
  2.1.100 [C:\Program Files\dotnet\sdk]
  2.1.104 [C:\Program Files\dotnet\sdk]
  2.1.300-rc1-008673 [C:\Program Files\dotnet\sdk]
  2.1.300 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.0-rc1-final [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.0-rc1-final [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 1.0.0-rc2-3002702 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 1.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 1.0.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 1.0.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 1.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 1.1.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 1.1.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.0.0-preview1-002111-00 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.0.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.0.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.0-rc1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]

To install additional .NET Core runtimes or SDKs:
  https://aka.ms/dotnet-download

VS Code version:1.24.1
C# Extension version:1.15.2

Steps to reproduce

1. create csharp script file(*.csx)
2. write using block like following

#! "netcoreapp2.0"

using(var sw = new StringWriter())
{
    sw.Write("abc");
}
Console.WriteLine("Hello world!");

Expected behavior

syntax highlighted like following image(only removed using)

Actual behavior

syntax highlighted like following image(red squared area is what I want to remark.)

[filipw]

This issue was moved to dotnet/csharp-tmLanguage#126

[filipw]

Thanks for the report - I moved this issue to the repo for the C# TextMate grammar in the dotnet organization, which is used for syntax highlighting C# in VS Code.