Fix for TypeExtensionPoint in generic classes

[pleonex]

This fix allows to have generic classes for plugins. For instance, the following interface will be the TypeExtensionPoint:

    [TypeExtensionPoint]
    public interface IConverter<in TSrc, out TDst>
    {
        TDst Convert(TSrc source);
    }

Then, we could have plugins implementing this class like:

    [Extension]
    public class Po2Binary : IConverter<Po, BinaryFormat>, IConverter<BinaryFormat, Po>
    {
        public BinaryFormat Convert(Po source)
        {
            // Implementation logic
        }

        public Po Convert(BinaryFormat source)
        {
            // Implementation logic
        }
    }

The problem was that the path variable contains the list of type names that the class implements. The types are separated by commas. In the case of generics, the type name contains also the list of types of the typeparam. for instance in this example, path contains:

Yarhl.FileFormat.IConverter`2[[Yarhl.FileFormat.BinaryFormat, Yarhl, Version=1.0.0.19273, Culture=neutral, PublicKeyToken=null],[Yarhl.Media.Text.Po, Yarhl.Media, Version=1.0.0.19273, Culture=neutral, PublicKeyToken=null]],Yarhl.FileFormat.IConverter`2[[Yarhl.Media.Text.Po, Yarhl.Media, Version=1.0.0.19273, Culture=neutral, PublicKeyToken=null],[Yarhl.FileFormat.BinaryFormat, Yarhl, Version=1.0.0.19273, Culture=neutral, PublicKeyToken=null]]

So if we just split by commas, we would get mix information with the generic types. Using the new approach we skip the information of the generic enclosed by [ ] so we get:

Yarhl.FileFormat.IConverter`2                                                                                                                                                                                
Yarhl.FileFormat.IConverter`2 

[dnfclas]

All CLA requirements met.

[Therzok]

This LGTM. cc @slluis