Use first line of comment as title of newtype param

[banool]

Description of the feature

See the test in poem/poem-openapi/tests/newtype.rs. The comment there all gets converted into a description. This is different to regular structs that derive Object, they use the first line for the summary. It would be cool if the first line of the struct was used as the param title.

Code example (if possible)

I would expect this test to pass:

#[tokio::test]
async fn new_type_summary_and_description() {
    /// MyString
    ///
    /// A
    /// B
    /// C
    #[derive(NewType)]
    struct MyString(String);

    let schema = MyString::schema_ref();
    let schema = schema.unwrap_inline();
    assert_eq!(schema.title, Some("MyString"));
    assert_eq!(schema.description, Some("A\nB\nC"));
}

I can look at adding this myself later.