[C# Dev Kit] Adding an interface file to the project prompts an error 'Naming rule violation: These words must begin with upper case characters: nterface1'

Platform | VSCode Version | Extension | Version | Comment
-- | -- | -- | -- | --
  |   | .NET Install Tool for Extension Authors | v1.6.0 | .NET Install Tool for Extension Authors - Visual Studio Marketplace
Windows, Mac M1, Linux | VSCode Insider 1.79.0    VSCode Stable 1.78.2 | C# Dev Kit     C# Extension | v0.0.904-alpha v2.0.140 | Pipelines - Run 0.0.904-alpha+7cee3ad678 (azure.com)Pipelines - Run 20230518.11 (visualstudio.com)

Repro rate: 100%

Steps to reproduce:
1. Create any project or open the folder including any project.
2. Add an Interface file to the project.

Expect Result:
Adding an interface file to the project does not prompt an error.

Actual Result:
Adding an interface file to the project prompts an error 'Naming rule violation: These words must begin with upper case characters: nterface1'.