Merge pull request rust-shell-script#11 from disco0/patch-1

Fix typo in Rust Cookbook link

Author: rust-shell-script

README.md

@@ -22,7 +22,7 @@ scripts grow, they will ultimately be unmaintainable and no one wants to touch t
 
 This cmd_lib library is trying to provide the redirection and piping capabilities, and other facilities to make writing
 shell-script like tasks easily without launching any shell. For the
-[rust cookbook examples](https://rust-lang-nursry.github.io/rust-cookbook/os/external.html),
+[rust cookbook examples](https://rust-lang-nursery.github.io/rust-cookbook/os/external.html),
 they can usually be implemented as one line of rust macro with the help of this library, as in the
 [examples/rust_cookbook_external.rs](https://github.com/rust-shell-script/rust_cmd_lib/blob/master/examples/rust_cookbook_external.rs).
 Since they are rust code, you can always rewrite them in rust natively in the future, if necessary without spawning external commands.