docs: fix some minor typos in the fs documentation
docs: fix some minor typos in the fs documentation

* fchmodSync: replace 'path' with 'fd'
* lchmod: replace 'fd' with 'path'
* utimes, futimes, fsync: mark 'callback' as optional

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node