fix(footnote): add return link to last element of reference element

Resolves #41

Author: micahkepe

content/markdown-demo.md

@@ -161,7 +161,20 @@ wrapping the text in square brackets and the URL in parentheses.
     amet id laboris pariatur ea ut exercitation Lorem velit et nisi nulla
     occaecat voluptate
 
-[^2]: Wikipedia article on a cool topic: [https://en.wikipedia.org/wiki/Isometric_projection](https://en.wikipedia.org/wiki/Isometric_projection)
+    ```rust
+    fn main() {
+        todo!();
+    }
+    ```
+
+[^2]:
+    Wikipedia article on a cool topic: [https://en.wikipedia.org/wiki/Isometric_projection](https://en.wikipedia.org/wiki/Isometric_projection)
+
+    > Isometric projection is a method for visually representing
+    > three-dimensional objects in two dimensions in technical and engineering
+    > drawings. It is an axonometric projection in which the three coordinate
+    > axes appear equally foreshortened and the angle between any two of them is
+    > 120 degrees.
 
 [^3]:
     Here's one with multiple paragraphs and code. This is the first paragraph

static/js/reference-return.js

@@ -27,12 +27,11 @@ document.addEventListener("DOMContentLoaded", function () {
     returnLink.setAttribute("role", "link");
     returnLink.setAttribute("tabindex", "0");
 
-    // Append to the last p tag
-    const lastParagraph = fn.querySelector("p:last-of-type");
-    if (lastParagraph) {
-      lastParagraph.appendChild(returnLink);
+    // Append inline to last paragraph, or after last element otherwise
+    const lastEl = fn.lastElementChild;
+    if (lastEl && lastEl.tagName === "P") {
+      lastEl.appendChild(returnLink);
     } else {
-      // If no paragraph, append to the footnote definition directly
       fn.appendChild(returnLink);
     }
   });