Fix doc test and typo

Author: dhardy

README.md

@@ -56,7 +56,7 @@ reading the [Upgrade Guide](https://rust-random.github.io/book/update.html).
 
 ### Rust version requirements
 
-The since version 0.5, Rand requires **Rustc version 1.22 or greater**.
+Since version 0.5, Rand requires **Rustc version 1.22 or greater**.
 Rand 0.4 and 0.3 (since approx. June 2017) require Rustc version 1.15 or
 greater. Subsets of the Rand code may work with older Rust versions, but this
 is not supported.

src/lib.rs

@@ -31,7 +31,7 @@
 //! let mut rng = rand::thread_rng();
 //! let y: f64 = rng.gen(); // generates a float between 0 and 1
 //!
-//! let nums: Vec<i32> = (1..100).collect();
+//! let mut nums: Vec<i32> = (1..100).collect();
 //! nums.shuffle(&mut rng);
 //! ```
 //!