markdown: Refactor code block copy button visibility to use enum (#52817)

Release Notes:

- N/A

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Signed-off-by: Xiaobo Liu <cppcoffee@gmail.com>
Co-authored-by: Finn Evers <finn.evers@outlook.de>
Co-authored-by: MrSubidubi <finn@zed.dev>
c5446117c1Xiaobo Liu committed on 4/1/2026, 9:05:03 AM· committed by GitHubparent23edf06
11 files changedLine totals unavailable