basics.md: delete defunct dingus

There is no dingus to play with; stop talking about it.

Also make the "syntax page" link hook up properly.

Signed-off-by: Kyle J. McKay <mackyle@gmail.com>

basics.md

@@ -13,16 +13,12 @@ Getting the Gist of Markdown's Formatting Syntax
 ------------------------------------------------
 
 This page offers a brief overview of what it's like to use Markdown.
-The [syntax page] [s] provides complete, detailed documentation for
+The [syntax page][syntax] provides complete, detailed documentation for
 every feature, but Markdown should be very easy to pick up simply by
 looking at a few examples of it in action. The examples on this page
 are written in a before/after style, showing example syntax and the
 HTML output produced by Markdown.
 
-It's also helpful to simply try Markdown out; the [Dingus] [d] is a
-web application that allows you type your own Markdown-formatted text
-and translate it to XHTML.
-
 **Note:** This document is itself written using Markdown; you
 can [see the source for it by adding `.md` to the URL] [src].