Function libpijul::fs::find_path

pub fn find_path<T: ChannelTxnT, C: ChangeStore>(
    changes: &C, 
    txn: &T, 
    channel: &T::Channel, 
    youngest: bool, 
    v: Position<ChangeId>
) -> Result<Option<(String, bool)>, FileError<C::Error, T::GraphError>>