Fix spelling mistakes

Author: pitdicker

benches/generators.rs

@@ -81,7 +81,7 @@ gen_uint_new!(gen_u64_std, u64, StdRng);
 gen_uint_new!(gen_u64_os, u64, OsRng);
 
 // Do not test JitterRng like the others by running it RAND_BENCH_N times per,
-// measurement, because it is way to slow. Only run it once
+// measurement, because it is way too slow. Only run it once.
 #[bench]
 fn gen_u64_jitter(b: &mut Bencher) {
     let mut rng = JitterRng::new().unwrap();

src/prng/chacha.rs

@@ -187,7 +187,7 @@ impl ChaChaRng {
 
     /// Refill the internal output buffer (`self.buffer`)
     fn update(&mut self) {
-        // For some reason extracting this part into a seperate function
+        // For some reason extracting this part into a separate function
         // improves performance by 50%.
         fn core(results: &mut [u32; STATE_WORDS],
                 state: &[u32; STATE_WORDS],