Update mapping.md

Author: dgarijo

docs/mapping.md

@@ -1,7 +1,7 @@
 The current mapping between OWL and OpenAPI specification (OAS) supported by OBA can be seen below.
 
 !!! warning
-  We are currently working on improving the mapping with complex axiomatization of domains and ranges and other property annotations (minimum and maximum cardinality, etc.)
+    We are currently working on improving the mapping with complex axiomatization of domains and ranges and other property annotations (minimum and maximum cardinality, etc.)
 
 **Namespaces** used in this document: