[Docs] Add references

docs/admin/20_configuration.rst

@@ -32,7 +32,7 @@ you can create such a user with something like:
 Configure database connection
 -----------------------------
 
-In the AlekSIS configuration file (cf. :ref:`core-configuraiton-files`,
+In the AlekSIS configuration file (cf. :ref:`core-configuration-files`),
 you have to set the following settings:
 
 .. code-block:: toml
@@ -99,7 +99,7 @@ How existing data is matched
 
 If there are already existing data in AlekSIS' database, the Untis import will
 always try to combine these data. The main data field used for this is the
-``short name`` field (cf. :ref:`core-concept-group`. If the data were imported
+``short name`` field (cf. :ref:`core-concept-group`). If the data were imported
 one time, each object in Chronos will save the respective ID from Untis to make
 sure that the data are properly updated at the next import.