fix: Use 'written_footnote_ix' (index) in place of named tag in subsequent references

Author: smockle

src/html.c

@@ -65,7 +65,7 @@ static bool S_put_footnote_backref(cmark_html_renderer *renderer, cmark_strbuf *
   renderer->written_footnote_ix = renderer->footnote_ix;
   char m[32];
   snprintf(m, sizeof(m), "%d", renderer->written_footnote_ix);
-  
+
   cmark_strbuf_puts(html, "<a href=\"#fnref-");
   houdini_escape_href(html, node->as.literal.data, node->as.literal.len);
   cmark_strbuf_puts(html, "\" class=\"footnote-backref\" data-footnote-backref aria-label=\"Back to reference ");
@@ -83,7 +83,7 @@ static bool S_put_footnote_backref(cmark_html_renderer *renderer, cmark_strbuf *
       cmark_strbuf_puts(html, "-");
       cmark_strbuf_puts(html, n);
       cmark_strbuf_puts(html, "\" class=\"footnote-backref\" data-footnote-backref aria-label=\"Back to reference ");
-      houdini_escape_href(html, node->as.literal.data, node->as.literal.len);
+      cmark_strbuf_puts(html, m);
       cmark_strbuf_puts(html, "-");
       cmark_strbuf_puts(html, n);
       cmark_strbuf_puts(html, "\">↩<sup class=\"footnote-ref\">");