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/roam.ipynb

@@ -1,11 +1,15 @@
 {
  "cells": [
   {
+   "attachments": {},
    "cell_type": "markdown",
    "id": "1dc7df1d",
    "metadata": {},
    "source": [
     "# Roam\n",
+    "\n",
+    ">[ROAM](https://roamresearch.com/) is a note-taking tool for networked thought, designed to create a personal knowledge base.\n",
+    "\n",
     "This notebook covers how to load documents from a Roam database. This takes a lot of inspiration from the example repo [here](https://github.com/JimmyLv/roam-qa).\n",
     "\n",
     "## 🧑 Instructions for ingesting your own dataset\n",
@@ -40,7 +44,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "loader = ObsidianLoader(\"Roam_DB\")"
+    "loader = RoamLoader(\"Roam_DB\")"
    ]
   },
   {
@@ -70,7 +74,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.10.9"
+   "version": "3.10.6"
   }
  },
  "nbformat": 4,