Error deserializing Owned data

[Jusduil]

Hello,

When deserialize Language from owned data (example with serde_json::from_reader or serde_json::from_value), deserializer fail.

dbg!(serde_json::from_value::<Language>(serde_json::json!("fr")))

= Err(
    Error("invalid type: string \"fr\", expected borrowed str or bytes", line: 0, column: 0),
)

This is because only visit_borrowed_str and visit_borrowed_bytes is implemented on Visitor.

    fn visit_borrowed_str<E>(self, v: &'a str) -> Result<Self::Value, E>
    where
        E: serde::de::Error,
    { ... }

    fn visit_borrowed_bytes<E>(self, v: &'a [u8]) -> Result<Self::Value, E>
    where
        E: serde::de::Error,
    { ... }

I propose to replace this implementation to implement visit_str and visit_bytes, this two methods accept data borrowed and owned. The default implementation of borrowed version forward to not borrowed version.

Thank you for considering this issue!