Upload Guillaume's heat flux plot

Author: GardevoirX

docs/src/outputs/index.rst

@@ -136,7 +136,7 @@ quantities, i.e. quantities with a well-defined physical meaning.
       :link: heat-fluxes-output
       :link-type: ref
 
-      .. image:: /../static/images/charges-output.png
+      .. image:: /../static/images/heat-flux-output.png
 
       Heat fluxes, i.e. the amount of energy transferred per unit time, i.e.
       :math:`\sum_i E_i \times \vec v_i`