Merge #163: Fix typo

68bb539 Fix typo (GoodDaisy)

Pull request description:

ACKs for top commit:
  apoelstra:
    ACK 68bb539

Tree-SHA512: ba935bde9c3a5efab55af093bfc902379f0d63dc1fb0b534e4eb20c91f309bf41b16e987f3f3421cd6c9388abafb2700e79fb68e55195db7f5f8a1ebd5753056

src/primitives/checksum.rs

@@ -161,7 +161,7 @@ pub trait PackedFe32: Copy + PartialEq + Eq + ops::BitXor<Self, Output = Self> {
     /// add a new field element to the now-0 constant coefficient.
     ///
     /// Takes the degree of the polynomial as an input; for checksum applications
-    /// this shoud basically always be `Checksum::CHECKSUM_WIDTH`.
+    /// this should basically always be `Checksum::CHECKSUM_WIDTH`.
     fn mul_by_x_then_add(&mut self, degree: usize, add: u8) -> u8;
 }