Coalesce Themes

[333fred]

Right now there are a bunch of different themes, based on the VS colors, but with slight differences. In the current version, we have:

• Dark+
• Dark Modern
• Dark (Visual Studio)
• Visual Studio 2019 Dark

The last one has some semantic themeing info the previous 3 do not (such as coloring classes/structs/interfaces differently to each other). We should deduplicate these where can.

[aradalvand]

Why not just get rid of "Visual Studio 2019 Dark" and add proper C# semantic highlighting to the new "Dark Modern" theme?

The main thing lacking in VS Code's C# tooling has always been proper syntax highlighting, comparable to that of Visual Studio. We always had to resort to adding custom settings to enhance the syntax highlighting (e.g. making namespces white, structs and interface different from classes, etc.), meanwhile it was always easy to make this part of the built-in theme.

Now is a good time to finally address this age-old problem.

[just-ero]

Another coloring issue I'd like to point out is properties and fields versus locals. In the Visual Studio 2019 Dark theme, properties and fields are colored white, locals are light blue. In the other themes, all 3 are the same color.

[xamir82]

This has always bugged me personally, hopefully it's fixed soon, finally.
The C# syntax highlighting in VS Code should just be brought to parity with Visual Studio. So that they look more or less identical.

[arunchndr]

Closing as dup of #5763

[just-ero]

#5763 came later and is much less complete in terms of information. How was this closed in favor of that?

[xamir82]

@arkalyanms Can you please respond to @just-ero's comment above?