Vwp/docs improved document loaders (#4006)

Huge thanks to @leo-gan for improving the document loaders notebooks

---------

Co-authored-by: Leonid Ganeline <leo.gan.57@gmail.com>

docs/modules/indexes/document_loaders/examples/blackboard.ipynb

@@ -1,13 +1,18 @@
 {
  "cells": [
   {
-   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [
     "# Blackboard\n",
     "\n",
-    "This covers how to load data from a Blackboard Learn instance."
+    "This covers how to load data from a [Blackboard Learn](https://www.anthology.com/products/teaching-and-learning/learning-effectiveness/blackboard-learn) instance.\n",
+    "\n",
+    "This loader is not compatible with all `Blackboard` courses. It is only\n",
+    "    compatible with courses that use the new `Blackboard` interface.\n",
+    "    To use this loader, you must have the BbRouter cookie. You can get this\n",
+    "    cookie by logging into the course and then copying the value of the\n",
+    "    BbRouter cookie from the browser's developer tools."
    ]
   },
   {
@@ -28,11 +33,24 @@
   }
  ],
  "metadata": {
-  "language_info": {
-   "name": "python"
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
   },
-  "orig_nbformat": 4
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.10.6"
+  }
  },
  "nbformat": 4,
- "nbformat_minor": 2
+ "nbformat_minor": 4
 }