Add warning about bad hyphens

src/main.rs

@@ -584,6 +584,9 @@ async fn main() -> Result<(), Error> {
                                 return Err(format_err!("Not high enough metrics ({:?} stars < {}, and {:?} cargo downloads < {}): {}", github_stars, required_stars, cargo_downloads, MINIMUM_CARGO_DOWNLOADS, list_item));
                             }
                             if link_count > 0 && !ITEM_REGEX.is_match(&list_item) {
+                                if list_item.contains("—") {
+                                    warn!("\"{list_item}\" uses a '—' hyphen, not the '-' hyphen and we enforce the use of the latter one");
+                                }
                                 return Err(format_err!("Item does not match the template: \"{list_item}\". See https://github.com/rust-unofficial/awesome-rust/blob/main/CONTRIBUTING.md#tldr"));
                             }
                             list_items.last_mut().unwrap().data.push(list_item.clone());