Remove unused rayon::prelude

Author: bact

src/tokenizer/dict_reader.rs

@@ -7,7 +7,6 @@
 use crate::four_bytes_str::custom_string::CustomString;
 
 use super::trie_char::TrieChar as Trie;
-use rayon::prelude::*;
 use std::io::BufReader;
 use std::{error::Error, io::prelude::*};
 use std::{fs::File, path::PathBuf};