Fix readme rendering. (#88)

README.rst

@@ -60,7 +60,8 @@ Python 3.9, as some Python library versions may not be available with
 earlier versions of Python. Moreover, its `end-of-life <https://endoflife.date/python>`__ 
 is Oct 2025.
 
-**Local machine**
+*Local machine setup*
+=====================
 
 Below are commands that worked for our configuration (Ubuntu
 21.04), but there are certainly other ways to download a repository and
@@ -83,9 +84,13 @@ install the library locally.
    # (optional) try reconstruction on local machine
    python scripts/recon/admm.py
 
+   # (optional) try reconstruction on local machine with GPU
+   python scripts/recon/admm.py -cn pytorch
 
-Note (25-04-2023): for using the reconstruction method based on Pycsou (now [Pyxu](https://github.com/matthieumeo/pyxu))
-``lensless.apgd.APGD``, a specific commit has to be installed (as there was no release at the time of implementation):
+
+Note (25-04-2023): for using the :py:class:`~lensless.recon.apgd.APGD` reconstruction method based on Pycsou
+(now `Pyxu <https://github.com/matthieumeo/pyxu>`__), a specific commit has 
+to be installed (as there was no release at the time of implementation):
 
 .. code:: bash
 
@@ -102,7 +107,8 @@ Moreover, ``numba`` (requirement for Pycsou V2) may require an older version of
 
    pip install numpy==1.23.5
 
-**Raspberry Pi**
+*Raspberry Pi setup*
+====================
 
 After `flashing your Raspberry Pi with SSH enabled <https://medium.com/@bezzam/setting-up-a-raspberry-pi-without-a-monitor-headless-9a3c2337f329>`__, 
 you need to set it up for `passwordless access <https://medium.com/@bezzam/headless-and-passwordless-interfacing-with-a-raspberry-pi-ssh-453dd75154c3>`__.