Use file-scoped namespace in .NET 6.0+ projects

[JasonWei512]

Use C# 10's file-scoped namespace when:

• The file to be created is a C# file
• The TargetFramework version of the current project is .NET 6.0+
• csharpextensions.useFileScopedNamespace is enabled in settings

[JasonWei512]

Thanks for your reply! I splited the double await line into 2 lines. And yes, the second await doesn't do anything, so I removed it.