Fix missing > in docs

Author: eopb

src/serde.rs

@@ -13,7 +13,7 @@ impl<'de, T: Deserialize<'de>> Deserialize<'de> for Secret<T> {
 /// A serializable type that contains a secret.
 ///
 /// This abstraction enables [expose_secret] to be used to serialize both `Secret<T>` and
-/// `Option<Secret<T>`.
+/// `Option<Secret<T>>`.
 ///
 /// This type is currently private. If you feel that a public `SerializableSecret` could
 /// be useful for your use case please open a PR :)