Improve documentation layout

Author: nyamsprod

docs/scripts.js

@@ -4,6 +4,7 @@
 
   const isHeading = el => el && el.nodeType === 1 && /^H[1-6]$/.test(el.tagName);
   const headers = root.querySelectorAll('h2, h3, h4, h5, h6');
+  const ids = new Set();
   headers.forEach(h => {
     let id = h.id || h.textContent.trim().toLowerCase().replace(/\W+/g, '-');
     let base = id;