Fix typo and update shortcodes body copy

content/content-management/markdown-and-supported-formats.md

@@ -20,7 +20,7 @@ notes:
 Markdown is the natively supported content format for Hugo and is rendered using the excellent [BlackFriday project][], a markdown parser written in Golang.
 
 {{% note "Deeply Nested Lists" %}}
-Hugo uses [BlackFriday](https://github.com/russross/blackfriday), a markdown processor written in Golang. BlackFriday has a known issues [(#329)](https://github.com/russross/blackfriday/issues/329) with handling deeply nested lists, but there is a workaround. If you write lists in markdown, be sure to include 4 spaces (i.e., <kbd>tab</kbd>) rather than 2 to delimit nesting of lists.
+Hugo uses [BlackFriday](https://github.com/russross/blackfriday), a markdown processor written in Golang. BlackFriday has a known issue [(#329)](https://github.com/russross/blackfriday/issues/329) with handling deeply nested lists, but there is a workaround. If you write lists in markdown, be sure to include 4 spaces (i.e., <kbd>tab</kbd>) rather than 2 to delimit nesting of lists.
 {{% /note %}}
 
 ## Additional Resources

content/content-management/shortcodes.md

@@ -160,7 +160,7 @@ Assuming that standard Hugo pretty URLs are turned on.
 <a href="/about/#who:c28654c202e73453784cfd2c5ab356c0">Who</a>
 ```
 
-### `tweet` (Twitter)
+### `tweet`
 
 You want to include a single tweet into your blog post? Everything you need is the URL of the tweet. For example, let's say you want to include the following tweet from `https://twitter.com/spf13/status/666616452582129664`. Pass the tweet's ID from the URL as parameter to the shortcode as shown below:
 
@@ -200,7 +200,7 @@ and pass it to the shortcode:
 {{</* vimeo 146022717 */>}}
 ```
 
-### `gist` (GitHub)
+### `gist`
 
 Including code snippets with GitHub gists while writing a tutorial is common situation bloggers face. With a given URL of the gist, e.g.: