chore: fix some comments

src/io/mod.rs

@@ -61,7 +61,7 @@ pub trait Read {
     /// If the return value of this method is [`Ok(n)`], then it must be
     /// guaranteed that `0 <= n <= buf.len()`. A nonzero `n` value indicates
     /// that the buffer `buf` has been filled in with `n` bytes of data from this
-    /// source. If `n` is `0`, then it can indicate that the the buffer
+    /// source. If `n` is `0`, then it can indicate that the buffer
     /// specified was 0 bytes in length.
     ///
     /// No guarantees are provided about the contents of `buf` when this

src/iterable/mod.rs

@@ -39,7 +39,7 @@ pub use rev::Reverse;
 /// assert_eq!(f(xs), g(xs));
 /// ```
 ///
-/// # Efficency
+/// # Efficiency
 ///
 /// For efficiency, functions using iterables are often times relying on
 /// [`Borrow`](std::borrow::Borrow) in order to avoid copying the contents of