message: Use a non-looping push to push a single element.
diff: @@ -85,7 +85,7 @@ impl CType {
  w.push_str("const ");
  }
  inner.generate_c(w);
  - w.push_str("*");
  + w.push('*');
  }
  Self::U8 => {
  w.push_str("unsigned char");
  