Fix ability to disable "no grammar" message

Fixes redhat-developervscode-xml#467

Signed-off-by: David Thompson <[email protected]>

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/extensions/contentmodel/settings/XMLValidationSettings.java

@@ -182,6 +182,7 @@ public XMLValidationSettings merge(XMLValidationSettings settings) {
 			this.namespaces = settings.namespaces;
 			this.schema = settings.schema;
 			this.enabled = settings.enabled;
+			this.noGrammar = settings.noGrammar;
 			this.disallowDocTypeDecl = settings.disallowDocTypeDecl;
 			this.resolveExternalEntities = settings.resolveExternalEntities;
 		}