Shows examples of all the markdown and keywords available for Swift headerdoc

Swift headerdoc examples

/**
 General description of the thing being documented. You can use:

 - markdown-style `backticks`
 - [urls pointing to pages like this one, that really helped me make this (thanks!)](http://ericasadun.com/2015/06/14/swift-header-documentation-in-xcode-7/)
 - HTML-style ascii codes (see copyright below)

 # Headers
 ## work
 ##### too

 *as do* **all** the ***emphasis*** levels

 ---
 ***
 - - -

 and horizontal rules

 	and this is how you make a code box

 and

 	another one

 * unordered lists
 * can use
 * the following delimiters:
 	* \+
 	* \*
 	* \-

 1. ordered
 2. lists
 3. use
 4. numbers

 Top level items: returns, parameters, throws (see example)
 - returns: description
 - parameter name: description
 - throws: list of errors

 Bolded subheaders:
 - attention: callout
 - author: name
 - authors: names
 - bug: description
 - complexity: O(1)
 - copyright: © year, name
 - date: the, uh, date
 - experiment: description
 - important: important note
 - invariant: description
 - note: not-as-important note
 - postcondition: description
 - precondition: description
 - remark: aside
 - requires: dependencies
 - seealso: another another method
 - since: some date
 - todo: action item
 - version: version
 - warning: warning
 */