Add suffix macro to bisync

[okhsunrog]

Similar to #8, this time using the new syntax:

#[bisync]
pub async fn get_some_data(&mut self) -> Result<Data, Error> {
    // Async: becomes self.device.read_async().await?
    // Sync:  becomes self.device.read()?
    let data = bisync::suffix!("_async", self.device.read().await?);
    Ok(data)
}

You can see an example of using this PR here: okhsunrog/axp192-dd

[okhsunrog]

I'd be grateful for reviewing this, as I want to publish my driver to crates.io and can't publish it till it has git dependencies