Adding signature help tooltip coloring support for VS

[navya9singh]

How Strada does it

• tsserver tags text with SymbolDisplayPartKind values (TypeScript's own enum)
• TypeScript-VS C# middleware translates these to Roslyn ClassificationTypeNames via GetClassificationName()
• Middleware builds a ClassifiedTextElement and attaches it as ColorizedLabel on SignatureInformation
• VS uses the Roslyn classification names to render colored text

Why Corsa needs a different approach

• In Corsa, VS talks directly to tsgo over LSP — no C# middleware exists in this path
• Without middleware, there's nothing to translate display part kinds or build the ClassifiedTextElement
• Result: signature help renders as plain uncolored text

New displayPartsWriter

• The Go printer's internal writer discards classification info — WriteKeyword, WriteSymbol, etc. all just append plain text
• Modifying the internal writer would add overhead to every print operation across the codebase
• displayPartsWriter implements EmitTextWriter as an external writer passed to printer.Write(), intercepting classified write calls and recording Roslyn classification names alongside text
• classificationForSymbol() collapses Strada's 2-step translation (SymbolFlags → SymbolDisplayPartKind → Roslyn name) into one step, verified against both displayPartKind() and GetClassificationName()

Changes

• Modified: internal/ls/signaturehelp.go - builds _vs_colorizedLabel with classified runs per signature

• Modified: internal/lsp/lsproto/_generate/generate.mts— added ClassifiedTextRun, ClassifiedTextElement types; patched SignatureInformation

• 23 baseline files updated with new _vs_colorizedLabel data

• displayPartsWriter is reusable for hover, FAR, completions — any feature needing VS colorized output

Fixes Bug 2800005

[navya9singh]

fixing this

[jakebailey]

Do we just need to enable the VS cap in fourslash?

[navya9singh]

Yes, if we enable the capability in fourslash then these responses will include the _vs_colorizedLabel. Should I do that?

[jakebailey]

Yes, I assume we want to make sure it's working, right?

[navya9singh]

Sure, I'll add it. I've tried it with VS and it works there and fixes the coloring issue.

[jakebailey]

I think we should try to test this, but otherwise LGTM

[jakebailey]

where did TestQualifyModuleTypeNames go?

[navya9singh]

I'm running these tests again to check