Merge pull request #214 from gooddata/mouchar-patch-1

TRIVIAL: Update example for list_data_sources

Reviewed-by: Jan Kadlec
             https://github.com/hkad98

docs/content/en/docs/data/data-source/list_data_sources.md

@@ -25,7 +25,7 @@ List of all data sources in the whole organization.
 
 ```Python
 # List all data sources
-data_sources = sdk.catalog_data_sources.list_data_sources()
+data_sources = sdk.catalog_data_source.list_data_sources()
 
 
 # [