Merge pull request #4147 from jakelevirne/master

Updated the description of Heading cells, which are no longer used

docs/source/examples/Notebook/What is the Jupyter Notebook.ipynb

@@ -142,18 +142,17 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "Notebooks consist of a **linear sequence of cells**. There are four basic cell types:\n",
+    "Notebooks consist of a **linear sequence of cells**. There are three basic cell types:\n",
     "\n",
     "* **Code cells:** Input and output of live code that is run in the kernel\n",
     "* **Markdown cells:** Narrative text with embedded LaTeX equations\n",
-    "* **Heading cells:** 6 levels of hierarchical organization and formatting\n",
     "* **Raw cells:** Unformatted text that is included, without modification, when notebooks are converted to different formats using nbconvert\n",
     "\n",
     "Internally, notebook documents are **[JSON](https://en.wikipedia.org/wiki/JSON) data** with **binary values [base64](http://en.wikipedia.org/wiki/Base64)** encoded. This allows them to be **read and manipulated programmatically** by any programming language. Because JSON is a text format, notebook documents are version control friendly.\n",
     "\n",
     "**Notebooks can be exported** to different static formats including HTML, reStructeredText, LaTeX, PDF, and slide shows ([reveal.js](http://lab.hakim.se/reveal-js/)) using Jupyter's `nbconvert` utility.\n",
     "\n",
-    "Furthermore, any notebook document available from a **public URL on or GitHub can be shared** via [nbviewer](http://nbviewer.jupyter.org). This service loads the notebook document from the URL and renders it as a static web page. The resulting web page may thus be shared with others **without their needing to install the Jupyter Notebook**."
+    "Furthermore, any notebook document available from a **public URL or on GitHub can be shared** via [nbviewer](http://nbviewer.jupyter.org). This service loads the notebook document from the URL and renders it as a static web page. The resulting web page may thus be shared with others **without their needing to install the Jupyter Notebook**."
    ]
   }
  ],
@@ -173,9 +172,9 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.4.0"
+   "version": "3.6.6"
   }
  },
  "nbformat": 4,
- "nbformat_minor": 0
+ "nbformat_minor": 1
 }