Fixed Python-Markdown#110. Documented the 'fenced_code' extension's s…

…upport for the 'codehilite' extension.

docs/extensions/fenced_code_blocks.txt

@@ -58,12 +58,25 @@ The above will output:
     <pre><code class="html">&lt;p&gt;HTML Document&lt;/p&gt;
     </code></pre>
 
+[Github][]'s tilde (`\``) syntax is also supported:
+
+    ```python
+    # more python code
+    ```
+
+[Github]: http://github.github.com/github-flavored-markdown/
+
 Usage
 -----
 
 From the Python interpreter:
 
     >>> html = markdown.markdown(text, ['fenced_code'])
 
+If you would like to have your fenced code blocks highlighted with the 
+[CodeHilite][] extension, simply include that extension and the language 
+of your fenced code blocks will be passed in and highlighted appropriately.
 
+    >>> html = markdown.markdown(text, ['fenced_code', 'codehilite'])
 
+[CodeHilite]: code_hilite.html