ReST: code-block role does not accept options

[Sébastien Bigaret <sbigaret@…>]

The way it is designed in 0.9.4, the code-block role does not accept any options, and the language is directly extracted from the content, such as in:

:code-block:`python:f = lambda x: x+2`

This prevents user from defining their own custom interpreted text roles.

The enclosed patch allows the definition of custom roles based on code-block, while preserving the default behaviour.

With the patch, the following code works as expected:

.. role:: py(code-block)
   :language: python

:py:`f = lambda x: x+2`

:code-block:`python:f = lambda x: x+2`

[Matthew Good]

Added in [2938]. Thanks for the patch.