Fix typo in message converter rust docs
@@ -19,7 +19,7 @@ use crate::error::InternalError;
/// Convert between two different message formats.
///
/// Commonly this conversion will be serialization and deserialization; for example, when
-/// converting between a internal struct format and `Vec<u8>`.
+/// converting between an internal struct format and `Vec<u8>`.
///
/// When implementing MessageConverter, two generic type parameters must be specified: `L` and `R`.
/// `L` is for the left side, `R` is for the right side. The functions `to_left` and `to_right`
