Print the contents of the expected token when a serialize assert fails
Print the contents of the expected token when a serialize assert fails

Before
```
expected Token::Str but serialized as Str(“F9168C5E-CEB2-4FAA-B6BF-329BF39FA1E4")
```
After
```
expected Token::Str(“f9168c5e-ceb2-4faa-b6bf-329bf39fa1e4”) but serialized as Str(“F9168C5E-CEB2-4FAA-B6BF-329BF39FA1E4")
```

serde-rs/serde