contributing.md: fix styling issues

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

docs/contributing.md

@@ -15,7 +15,8 @@ on github.
 If you'd rather not use github you are more than welcome to send git formatted
 patches to brendan.le.foll@intel.com.
 
-# Basic rules
+Basic rules
+-----------
 - Your code must build
 - Commits must have a sign-off line by at least yourself
 - Commits must be named <file/module>: Some decent description
@@ -25,7 +26,7 @@ patches to brendan.le.foll@intel.com.
 - Try to stick to the established coding style reguardless of your personal feeling for it!
 
 Code signing
-============
+------------
 
 The sign-off is a simple line at the end of the explanation for the
 patch, which certifies that you wrote it or otherwise have the right to pass it
@@ -62,5 +63,4 @@ then you just add a line saying
 
 	Signed-off-by: Random J Developer <random@developer.example.org>
 
-using your real name (sorry, no pseudonyms or anonymous contributions.)
-Unsigned commits will not be accepted.
+Using your real name (sorry, no pseudonyms or anonymous contributions.)