md document format code example

Example 1: md format

I think you should use an
`<addr>` element here instead.

Example 2: md format

![GitHub Logo](/images/logo.png)
Format: ![Alt Text](url)

Example 3: md format

- [x] @mentions, #refs, [links](), **formatting**, and <del>tags</del> supported
- [x] list syntax required (any unordered or ordered list supported)
- [x] this is a complete item
- [ ] this is an incomplete item

Example 4: md format

* Item 1
* Item 2
  * Item 2a
  * Item 2b