clangd: Fix switch source header action on windows (#42105)

Fixes https://github.com/zed-industries/zed/issues/40935

Release Notes:

- Fixed clangd's switch source header action not working on windows
9c8e37a156Lukas Wirth committed on 11/6/2025, 3:12:34 PM· committed by GitHubparentd54c64f
1 file changedLine totals unavailable