Fixed spelling errors, added oxford comma

License: MIT
Signed-off-by: Richard Littauer <richard.littauer@gmail.com>

core/commands/unixfs/unixfs.go

@@ -6,8 +6,8 @@ var UnixFSCmd = &cmds.Command{
 	Helptext: cmds.HelpText{
 		Tagline: "Interact with ipfs objects representing Unix filesystems.",
 		ShortDescription: `
-'ipfs file' provides a familar interface to filesystems represtented
-by IPFS objects that hides IPFS-implementation details like layout
+'ipfs file' provides a familiar interface to file systems represented
+by IPFS objects, which hides IPFS implementation details like layout
 objects (e.g. fanout and chunking).
 `,
 		Synopsis: `