Debounce search input

script.js

@@ -53,12 +53,16 @@ Array.from(firstByLetter.entries())
   });
 
 const searchInput = document.getElementById("toc-search");
+let searchTimeout;
 searchInput?.addEventListener("input", (event) => {
+  clearTimeout(searchTimeout);
+  searchTimeout = setTimeout(() => {
     const query = event.target.value.trim().toLowerCase();
     Array.from(tocList?.querySelectorAll("li") ?? []).forEach((item) => {
       const text = item.textContent.toLowerCase();
       item.style.display = text.includes(query) ? "" : "none";
     });
+  }, 150);
 });
 
 // OCR/formatting errors from epub conversion