remove footnote, seems wrong

remove link, only use link to xmlschema-2

documentation/IDTA-01001/modules/ROOT/pages/spec-metamodel/datatypes.adoc

@@ -12,7 +12,7 @@ SPDX-License-Identifier: CC-BY-4.0
 
 == Predefined Simple Data Types
 
-The metamodel of the Asset Administration Shell uses some of the predefined simple data types of the  link:https://www.w3.org/XML/Core/[XML Schema Definition] (XSD) as its basic data types footnote:[https://www.w3.org/XML/Core/, former https://www.w3.org/TR/xmlschema-2/#built-in-datatypes].
+The metamodel of the Asset Administration Shell uses some of the predefined simple data types of the  XML Schema Definition (XSD) as its basic data types.
 See <<table-simple-data-types>> for an overview of the used types.
 Their definition is outside the scope of this document.