doc typo in fchmodat
doc typo in fchmodat

fchmod should be fchmodat

Signed-off-by: ed neville <a162caffcb6897220f4d1cf28164d73cb91993a8@s5h.net>

geofft/nix-rust,carllerche/nix-rust,geofft/nix-rust,carllerche/nix-rust,asomers/nix,carllerche/nix-rust,nix-rust/nix,asomers/nix,geofft/nix-rust,nix-rust/nix