fix: footnotes

src/markdown.rs

@@ -351,7 +351,7 @@ pub fn markdown_to_html(markdown: &str, _file_path: &str) -> String {
             Event::FootnoteReference(fref) => {
                 let _ = write!(
                     html_output,
-                    "<sup><a href=\"#{fref}\" id=\"{fref}\"></a></sup>"
+                    "<sup><a href=\"#{fref}\" id=\"{fref}\">{fref}</a></sup>"
                 );
             }