Fix typo (#1321)

doc/tutorial/single_cell_recipe.rst

@@ -65,7 +65,7 @@ It returns `0` by default and models without cells are quite boring!
             arbor.recipe.__init__(self)
             self.the_cell = cell
             self.the_probes = probes
-            self.the_props = arbor.neuron_cable_propetries()
+            self.the_props = arbor.neuron_cable_properties()
             self.the_cat = arbor.default_catalogue()
             self.the_props.register(self.the_cat)