[Feature Request] Make `#[serde(rename_all = "")]` support independent number

#[derive(Serialize)]
#[serde(rename_all = "snake_case")]
pub enum Chapter {
    Have1Apple, // will be "have1_apple"
}

#[derive(Serialize)]
#[serde(rename_all = "snake_case", independent_number = true)]
pub enum Chapter {
    Have1Apple, // want to be "have_1_apple"
}