tweak name of unused const

just why

src/main.rs

@@ -134,10 +134,7 @@ pub struct Config {
 const DEFAULT_OUTPUT_PATH: &str = "output";
 const DEFAULT_USER_AGENT: &str = concat!("registry-backup/v", clap::crate_version!());
 
-// const DEFAULT_INDEX: &str = "https://github.com/rust-lang/crates.io-index.git";
-// fn default_index() -> String {
-//     DEFAULT_INDEX.to_string()
-// }
+//const CRATESIO_INDEX: &str = "https://github.com/rust-lang/crates.io-index.git";
 
 fn default_output_path() -> PathBuf {
     PathBuf::from(DEFAULT_OUTPUT_PATH)