add complement wrapper xtask script

xtask/src/main.rs

@@ -0,0 +1,30 @@
+mod complement;
+
+use std::process::ExitCode;
+
+use clap::{Parser, Subcommand};
+
+#[derive(Parser)]
+struct Args {
+    #[clap(subcommand)]
+    command: Command,
+}
+
+#[derive(Subcommand)]
+enum Command {
+    Complement(complement::Args),
+}
+
+fn main() -> ExitCode {
+    let args = Args::parse();
+    let result = match args.command {
+        Command::Complement(args) => complement::main(args),
+    };
+    let Err(e) = result else {
+        return ExitCode::SUCCESS;
+    };
+    // Include a leading newline because sometimes an error will occur in
+    // the middle of displaying a progress indicator.
+    eprintln!("\n{e:?}");
+    ExitCode::FAILURE
+}