[Doc] Document the ReactorSurface class in Python

Fixes #407

doc/sphinx/cython/zerodim.rst

@@ -56,7 +56,6 @@ FlowReactor
 ^^^^^^^^^^^
 .. autoclass:: FlowReactor(contents=None, *, name=None, energy='on')
 
-
 Walls
 -----
 
@@ -68,6 +67,13 @@ WallSurface
 ^^^^^^^^^^^
 .. autoclass:: WallSurface(wall, side)
 
+Surfaces
+--------
+
+ReactorSurface
+^^^^^^^^^^^^^^
+.. autoclass:: ReactorSurface(kin=None, r=None, *, A=None)
+
 Flow Controllers
 ----------------
 

interfaces/cython/cantera/reactor.pyx

@@ -430,6 +430,8 @@ cdef class ReactorSurface:
     :param kin:
         The `Kinetics` or `Interface` object representing reactions on this
         surface.
+    :param r:
+        The `Reactor` into which this surface should be installed.
     :param A:
         The area of the reacting surface [m^2]
     """