Revise extended syntax

Author: mattcone

_extended-syntax/availability.md

@@ -7,7 +7,7 @@ Not all Markdown applications support extended syntax elements. You'll need to c
 
 ### Lightweight Markup Languages
 
-There are several lightweight markup languages that are *supersets* of Markdown. They include Gruber's basic syntax and build upon it by adding additional elements like tables, code blocks, syntax highlighting, URL auto-linking, and footnotes. Many of the most popular Markdown applications use one of the following lightweight markup languages:
+There are several lightweight markup languages that are *supersets* of Markdown. They include basic syntax and build upon it by adding additional elements like tables, code blocks, syntax highlighting, URL auto-linking, and footnotes. Many of the most popular Markdown applications use one of the following lightweight markup languages:
 
 - [CommonMark](https://commonmark.org)
 - [GitHub Flavored Markdown (GFM)](https://github.github.com/gfm/)

_extended-syntax/highlight.md

@@ -9,12 +9,12 @@ This isn't common, but some Markdown processors allow you to highlight text. The
 I need to highlight these ==very important words==.
 ```
 
-The HTML looks like this:
+The rendered output looks like this:
 
-```html
 I need to highlight these <mark>very important words</mark>.
-```
 
-The rendered output looks like this:
+Alternatively, if your Markdown application supports [HTML](/basic-syntax/#html), you can use the `mark` HTML tag.
 
-I need to highlight these <mark>very important words</mark>.
+```html
+I need to highlight these <mark>very important words</mark>.
+```

_extended-syntax/overview.md

@@ -3,6 +3,6 @@ title: Overview
 syntax-id: overview
 ---
 
-The [basic syntax](/basic-syntax) outlined in John Gruber's original design document added many of the elements needed on a day-to-day basis, but it wasn't enough for some people. That's where extended syntax comes in.
+The [basic syntax](/basic-syntax) outlined in the original Markdown design document added many of the elements needed on a day-to-day basis, but it wasn't enough for some people. That's where extended syntax comes in.
 
 Several individuals and organizations took it upon themselves to extend the basic syntax by adding additional elements like tables, code blocks, syntax highlighting, URL auto-linking, and footnotes. These elements can be enabled by using a lightweight markup language that builds upon the basic Markdown syntax, or by adding an extension to a compatible Markdown processor.

extended-syntax.md

@@ -2,7 +2,7 @@
 layout: default
 title: Extended Syntax
 description: Advanced features that build on the basic Markdown syntax.
-last_modified_at: 2021-12-29
+last_modified_at: 2022-01-03
 ---
 
 {% include syntax.html type="extended" syntax-id="overview" %}