Includes notebook in documentation index

Author: spjuhel

doc/user-guide/adaptation.rst

@@ -9,6 +9,6 @@ These guides show everything you need to know in order to evaluate adapation opt
 
     .. Adaptation measures in CLIMADA <climada_measures.ipynb>
     Using measure configurations <climada_measure_config.ipynb>
-    .. Defining measure cash flows <climada_cost_income.ipynb>
+    Defining measure cash flows <climada_cost_income.ipynb>
     .. Cost benefit evaluation <climada_cost_benefit.ipynb>
     .. Adapation planning evaluation <climada_planning_evaluation.ipynb>