Add some whitespace around code blocks (#89)

* Add some whitespace around code blocks

* cargo fmt

Author: JSorngard

src/check.rs

@@ -12,6 +12,7 @@ use crate::integer_math::{mod_mul, mod_pow};
 /// # Example
 ///
 /// Basic usage:
+///
 /// ```
 /// # use const_primes::is_prime;
 /// const CHECK: bool = is_prime(18_446_744_073_709_551_557);

src/count.rs

@@ -7,6 +7,7 @@ use crate::sieve;
 /// # Example
 ///
 /// Basic usage
+///
 /// ```
 /// # use const_primes::prime_pi;
 /// const COUNTS: [usize; 10] = prime_pi();