Some features adjustment on MetadataFormat

I modified these issues:
- Added F# special member for type: UnionCase and RecordField, they are listed as members in Type;
- Make some change in displaying the members' usage (all because in real project, TypeName usually is very long):
  - For constructor, use "new(arg1, arg2, ...)" instead of "new TypeName" because in real project, TypeName usually is very long.
  - For instance members, discard the instance name, just show the method name and its arguments;
  - For static methods, discard the type name.
- Modifed the templates to show the special members of type, and also list nested types in module.

I also find another bug, that the private constructor is also listed. I traced this problem and find that it is a FSharpPowerPack.Metadata problem, so I also make a FSharpPowerPack repo, and fixed it by just one line, you can check that here: https://github.com/soloman817/FSharpPowerPack/commit/05182d5e95e425c27f04043b002933afa4447b4c