[NFC] Refactor IsTypeDeducibleWithAuto into HlslTypes

[Chris B (llvm-beanz)]

This function really should be one of the standalone type query functions rather than being on Sema, and since it doesn't depend on sema in any way it was a bit odd to have it that way to begin with.

[Copilot]

🟢 Approval recommended

The refactor preserves behavior; the missing direct include is a minor maintainability issue.

Pull request overview

Refactors the HLSL auto type-deducibility query from Sema into the AST type utilities without changing behavior.

Changes:

• Moves the implementation and declaration into HlslTypes.
• Updates the Sema call site to use the standalone query.

File summaries

File	Description
tools/clang/lib/Sema/SemaHLSL.cpp	Removes the Sema-owned implementation.
tools/clang/lib/Sema/SemaDecl.cpp	Calls the standalone AST query.
tools/clang/lib/AST/HlslTypes.cpp	Adds the relocated implementation.
tools/clang/include/clang/Sema/SemaHLSL.h	Removes the old Sema declaration.
tools/clang/include/clang/AST/HlslTypes.h	Exposes the query through the AST API.

Review details

• Files reviewed: 5/5 changed files
• Comments generated: 1
• Review effort level: Balanced

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[Copilot]

🟢 Approval recommended

The implementation is moved unchanged, all references are updated, and the NFC refactor does not require release notes.

Review details

• Files reviewed: 5/5 changed files
• Comments generated: 0 new
• Review effort level: Balanced