style(rust): Format all Rust code with rustfmt

Change-Id: Iab7e00cc26a4f9727d3ab98691ef379921a33052
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5240
Tested-by: BuildkiteCI
Reviewed-by: kanepyork <rikingcoding@gmail.com>
Reviewed-by: Profpatsch <mail@profpatsch.de>
Reviewed-by: grfn <grfn@gws.fyi>
Reviewed-by: tazjin <tazjin@tvl.su>

tools/cheddar/src/lib.rs

@@ -8,12 +8,10 @@ use lazy_static::lazy_static;
 use regex::Regex;
 use std::cell::RefCell;
 use std::collections::HashMap;
-use std::env;
 use std::ffi::OsStr;
-use std::io;
-use std::io::BufRead;
-use std::io::Write;
+use std::io::{BufRead, Write};
 use std::path::Path;
+use std::{env, io};
 use syntect::dumps::from_binary;
 use syntect::easy::HighlightLines;
 use syntect::highlighting::{Theme, ThemeSet};