Fix typos in ToHex Doc comments

src/lib.rs

@@ -59,11 +59,11 @@ pub use crate::serde::{deserialize, serialize, serialize_upper};
 ///
 /// *Note*: instead of using this trait, you might want to use [`encode()`].
 pub trait ToHex {
-    /// Encode the hex strict representing `self` into the result.. Lower case
+    /// Encode the hex strict representing `self` into the result. Lower case
     /// letters are used (e.g. `f9b4ca`)
     fn encode_hex<T: iter::FromIterator<char>>(&self) -> T;
 
-    /// Encode the hex strict representing `self` into the result.. Lower case
+    /// Encode the hex strict representing `self` into the result. Upper case
     /// letters are used (e.g. `F9B4CA`)
     fn encode_hex_upper<T: iter::FromIterator<char>>(&self) -> T;
 }