VB .Net documentation creates code tags with lang-csharp style with the default template.

**DocFX Version Used**:
2.23.1

**Template used**: (`default` or `statictoc` or contain custom template)
default

**Steps to Reproduce**:

1. Create a VB .NET project.
2. Add some source code with XML documentation.
3. Add DocFX
4. Compile.

**Expected Behavior**:
All code blocks should be created with class vbnet for .vb files.

**Actual Behavior**:
Only XML comments with example tags are generated with vbnet class. Syntax, constructors, methods and declaration are all with lang-csharp class, so the code shown is csharp, not VB.