Unifiedparser: Add support for VB.NET

# Feature request

Old projects that rely on C#, often also have a lot of VB.NET (some even VB6, VBA and VBScript, but let's ignore those for the moment). The unifiedparser is currently blind to these.

## Description

As a legacy archeologist, I want VB.NET parsing so that legacy complexity cannot stay hidden there.

## Acceptance criteria
- The unifiedparser can also parse VB.NET

## Assumptions & Exclusions

We assume here that VB6, VBA and VBScript are not as important as VB.NET. These languages do not run in the .NET CLR, so hopefully that means they are also significantly less common.

Start by locating the unifiedparser and reading how its existing C# parsing path is structured. Inspect any parser tests and determine the expected VB.NET coverage; the work is done when the unifiedparser can parse VB.NET as stated in the acceptance criteria.

Written by the indexing model from the issue text.