Few replaces from config.qfq.php in Documentations.

(cherry picked from commit f56004e2)

Documentation/Concept.rst

@@ -294,7 +294,7 @@ in `indexQfq`. If specific forms or reports should use a different database than
 A `Form` will:
 
 * load the form-definition from `indexQfq` (table `Form` and `FormElement`),
-* loads and save data from/in `indexData` (config.qfq.php) / `dbIndex` (form.parameter.dbIndex),
+* loads and save data from/in `indexData` (qfq.json) / `dbIndex` (form.parameter.dbIndex),
 * retrieve extra information via `dbIndexExtra` - this is useful to offer information from a database and save them in a
   different one.