Do not require passing token ids by value in decode

[zaycev]

Looking at https://github.com/zurawiki/tiktoken-rs/blob/main/tiktoken-rs/src/patched_tiktoken.rs#L64C1-L85C6

Why would the API require passing tokens by value and immediately taking reference?

    /// Decode a vector of tokens into a valid UTF-8 String
    ///
    /// If unicode validation is not wanted, see _decode_native.
    pub fn decode(&self, tokens: Vec<Rank>) -> Result<String> {
        match String::from_utf8(self.decode_bytes(&tokens)?) {
            Ok(text) => Ok(text),
            Err(e) => Err(anyhow!("Unable to decode into a valid UTF-8 string: {}", e)),
        }
    }

    pub fn _decode_native_and_split(
        &self,
        tokens: Vec<Rank>,
    ) -> impl Iterator<Item = Vec<u8>> + '_ {
        tokens.into_iter().map(|token| {
            let token_bytes = self
                .decoder
                .get(&token)
                .unwrap_or_else(|| &self.special_tokens_decoder[&token]);
            token_bytes.clone()
        })
    }