Use proper syntax highlighting for XML examples

src/asciidoc/core-beans.adoc

@@ -1719,7 +1719,7 @@ then nested `constructor-arg` elements.
 
 Let's review the examples from <<beans-constructor-injection>> with the `c:` namespace:
 
-[source,java,indent=0]
+[source,xml,indent=0]
 [subs="verbatim,quotes"]
 ----
 	<beans xmlns="http://www.springframework.org/schema/beans"
@@ -1753,7 +1753,7 @@ For the rare cases where the constructor argument names are not available (usual
 the bytecode was compiled without debugging information), one can use fallback to the
 argument indexes:
 
-[source,java,indent=0]
+[source,xml,indent=0]
 [subs="verbatim,quotes"]
 ----
 	<!-- c-namespace index declaration -->