Fixup generated code

Author: alexcrichton

Diff for: crates/web-sys/src/features/mod.rs

@@ -1,5 +1,3 @@
-#![allow(non_snake_case, unused_imports)]
-
 #[cfg(feature = "AbortController")]
 mod gen_AbortController;
 #[cfg(feature = "AbortController")]

Diff for: crates/webidl/src/main.rs

@@ -1,12 +1,7 @@
 use anyhow::{Context, Result};
-use sourcefile::SourceFile;
-use std::collections::BTreeMap;
-use std::ffi::OsStr;
 use std::fs;
-use std::path::{Path, PathBuf};
-use std::process::Command;
+use std::path::PathBuf;
 use structopt::StructOpt;
-use wasm_bindgen_webidl::Feature;
 
 #[derive(StructOpt, Debug)]
 #[structopt(