Correct broken xml on md document for DCCValidator

DCC-validator/installation.md

@@ -97,9 +97,9 @@ Install factories module
 
 5. Stop Wildfly and edit standalone.xml in `/usr/local/wildfly18/standalone/configuration` ; add the factories binding in the naming subsystem :
 
-Replace this property `${DEPLOYMENT_PROPERTIES}` with your own path to the deployment property:
+   Replace this property `${DEPLOYMENT_PROPERTIES}` with your own path to the deployment property:
 
-   ```txt
+   ```xml
    <subsystem xmlns="urn:jboss:domain:naming:2.0">
       <bindings>
          <object-factory name="java:/app/gazelle/dcc-validator/operational-preferences" module="net.ihe.gazelle.factories" class="net.ihe.gazelle.factories.PropertiesFactory">