chore: ♻️ remove jquery (#1964)

* add scroll-to-top and scroll class toggle with vanilla JS

* add language detection

* add  i18n

* Fix bug: there was no class hidden in CSS. Notice was hidden by hide(). Now HTML hidden attribute is used to hide notice using CSS. This improves A11y.

* fix flashing of i18n notice and improve a11y

* add menu highlighting on scroll

* ♻️ remove jquery

* defer app.js

Co-authored-by: Sebastian Beltran <bjohansebas@gmail.com>

* remove DOMContentLoaded and fix root margin to 25%

---------

Co-authored-by: bjohansebas <103585995+bjohansebas@users.noreply.github.com>

css/style.css

@@ -474,7 +474,7 @@ pre:has(code) button.failed {
   }
 }
 
-/* top button */
+/* scroll to top button */
 
 .scroll #top {
   opacity: .5;
@@ -611,6 +611,7 @@ table ul {
   font-weight: 600;
 }
 
+/* i18n box */
 .doc-notice {
   padding-block: 1rem;
   padding-inline: 2.5rem;
@@ -618,6 +619,11 @@ table ul {
   border-radius: 0 6px 6px 0;
   background: var(--notice-bg);
   border-left: 3px solid var(--notice-accent);
+  margin-inline: auto;
+  margin-block-start: 2rem;
+  position: relative;
+  grid-area: i18n;
+  display: block;
 }
 
 .doc-notice a{
@@ -625,6 +631,10 @@ table ul {
   text-decoration: underline;
 }
 
+.doc-notice[hidden] {
+  display: none;
+}
+
 .doc-info {
   background: var(--info-bg);
   border-left: 3px solid var(--info-accent);
@@ -645,13 +655,6 @@ table ul {
   text-decoration: underline;
 }
 
-#i18n-notice-box {
-  margin-inline: auto;
-  margin-block-start: 2rem;
-  position: relative;
-  grid-area: i18n;
-}
-
 #close-i18n-notice-box {
   position: absolute;
   top: 3px;