refactor(deps): upgrade bootstrap from v4.6 to v5.2

- update class name of the spacing, font style, cards and toasts
- update attribute names &  tooltip usage
- remove custom smooth scroll
- syntax colors

_layouts/default.html

@@ -25,7 +25,7 @@ layout: compress
     {% include topbar.html lang=lang %}
 
     <div id="main-wrapper" class="d-flex justify-content-center">
-      <div id="main" class="container pl-xl-4 pr-xl-4">
+      <div id="main" class="container px-xxl-5">
         {{ content }}
       </div>
 
@@ -52,16 +52,19 @@ layout: compress
         role="alert"
         aria-live="assertive"
         aria-atomic="true"
-        data-animation="true"
-        data-autohide="false"
+        data-bs-animation="true"
+        data-bs-autohide="false"
       >
         <div class="toast-header">
-          <button type="button" class="ml-2 ml-auto close" data-dismiss="toast" aria-label="Close">
-            <span aria-hidden="true">&times;</span>
-          </button>
+          <button
+            type="button"
+            class="btn-close ms-auto"
+            data-bs-dismiss="toast"
+            aria-label="Close"
+          ></button>
         </div>
         <div class="toast-body text-center pt-0">
-          <p class="pl-2 pr-2 mb-3">{{ site.data.locales[lang].notification.update_found }}</p>
+          <p class="px-2 mb-3">{{ site.data.locales[lang].notification.update_found }}</p>
           <button type="button" class="btn btn-primary" aria-label="Update">
             {{ site.data.locales[lang].notification.update }}
           </button>