file_util: fix broken symlink on Windows #8042

Job	Run time
check (clippy)	1m 34s
check (rustfmt)	30s
nix flake (ubuntu-24.04-arm)	7m 52s
nix flake (ubuntu-24.04)	7m 54s
nix flake (macos-14)	13m 5s
check (codespell)	11s
check (cargo-deny, bans)	25s
check (cargo-deny, advisories)	28s
check (cargo-deny, licenses)	25s
check (protos)	44s
check (cargo-deny, sources)	28s
test (linux-x86_64-gnu)	6m 20s
test (macos-aarch64)	8m 5s
test (macos-x86_64)	21m 28s
test (windows-aarch64)	17m 50s
test (linux-aarch64-gnu)	7m 1s
build (no git)	1m 32s
test (windows-x86_64)	17m 45s
check (mkdocs)	18s
check (latest mkdocs, optional)	15s
check (zizmor)	17s
check (Cargo.lock dependency count)	4s
check (doctests)	2m 57s
required checks (merge queue)	0s
	1h 57m 28s

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