Fix doc test and move external documentation link to rand_bytes function

openssl/src/rand.rs

@@ -1,20 +1,15 @@
-//! Cryptographically strong random bytes.
-//!
-//! This module exposes functionality to put cryptographically strong
-//! pseudo-random bytes into a buffer.
+//! Utilities for secure random number generation.
 //!
 //! # Examples
 //!
 //! To generate a buffer with cryptographically strong bytes:
 //!
 //! ```
-//! let muf buf = [0; 256];
+//! use openssl::rand::rand_bytes;
+//!
+//! let mut buf = [0; 256];
 //! rand_bytes(&mut buf).unwrap();
 //! ```
-//!
-//! # External OpenSSL Documentation
-//!
-//! [RAND_bytes](https://www.openssl.org/docs/man1.1.0/crypto/RAND_bytes.html)
 use libc::c_int;
 use ffi;
 
@@ -22,6 +17,21 @@ use cvt;
 use error::ErrorStack;
 
 /// Fill buffer with cryptographically strong pseudo-random bytes.
+///
+/// # Examples
+///
+/// To generate a buffer with cryptographically strong bytes:
+///
+/// ```
+/// use openssl::rand::rand_bytes;
+///
+/// let mut buf = [0; 256];
+/// rand_bytes(&mut buf).unwrap();
+/// ```
+///
+/// # External OpenSSL Documentation
+///
+/// [RAND_bytes](https://www.openssl.org/docs/man1.1.0/crypto/RAND_bytes.html)
 pub fn rand_bytes(buf: &mut [u8]) -> Result<(), ErrorStack> {
     unsafe {
         ffi::init();