feat(gui): add label about the multi select implementation

Signed-off-by: Pranav C <pranavxc@gmail.com>

packages/nc-gui/components/virtual-cell/components/ListItems.vue

@@ -246,8 +246,13 @@ watch(vModel, (nextVal) => {
             show-less-items
           />
         </div>
+
+        <div class="text-xs text-gray-400 text-center px-2 mt-4 pb-0">
+          * Use <kbd>ALT</kbd> / <kbd>OPT</kbd> + <kbd>Click</kbd> to select multiple records
+        </div>
       </template>
 
+
       <a-empty v-else class="my-10" :image="Empty.PRESENTED_IMAGE_SIMPLE" />
 
       <Suspense>