small doc fix in nbconvert

IPython/nbconvert/transformers/base.py

@@ -32,8 +32,8 b' class Transformer(NbConvertBase):'
     Any configurable traitlets this class exposed will be configurable in profiles
     using c.SubClassName.atribute=value
 
-    you can overwrite transform_cell to apply a transformation independently on each cell
-    or __call__ if you prefer your own logic. See corresponding docstring for informations.
+    you can overwrite `transform_cell` to apply a transformation independently on each cell
+    or `call` if you prefer your own logic. See corresponding docstring for informations.
 
     Disabled by default and can be enabled via the config by
         'c.YourTransformerName.enabled = True'