Leave Aliki TOC nesting to the heading level change

#1842 fixes the method group nesting by emitting h2 headings in
the default section, so the TOC needs no special case for them.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gxq9jGyjWoANhMZXRtssiu

Author: claude

lib/rdoc/generator/template/aliki/js/aliki.js

@@ -267,7 +267,8 @@ function generateToc() {
     if (!heading.id) return;
 
     const li = document.createElement('li');
-    li.className = `toc-item toc-${tocLevel(heading)}`;
+    const level = heading.tagName.toLowerCase();
+    li.className = `toc-item toc-${level}`;
 
     const link = document.createElement('a');
     link.href = `#${heading.id}`;
@@ -291,17 +292,6 @@ function generateToc() {
   }
 }
 
-// Constants, Attributes and method group headings are h3 so they nest under a
-// titled section's h2. In the untitled section, list them as h2 so they don't
-// look like children of the class comment's last heading.
-function tocLevel(heading) {
-  const level = heading.tagName.toLowerCase();
-  if (level !== 'h3' || !heading.matches('.documentation-section > section > header > h3')) return level;
-
-  const section = heading.closest('.documentation-section');
-  return section.querySelector(':scope > .documentation-section-title') ? level : 'h2';
-}
-
 function hookTocActiveHighlighting() {
   const tocLinks = document.querySelectorAll('.toc-link');
   const targetHeadings = [];