Fix nullable annotations of RClientGraphicFactory.getInitServerProperties

The explicit type bound 'Object' is not affected by the nullness default.
diff --git a/core/org.eclipse.statet.rj.client/src/org/eclipse/statet/rj/server/client/RClientGraphicDummyFactory.java b/core/org.eclipse.statet.rj.client/src/org/eclipse/statet/rj/server/client/RClientGraphicDummyFactory.java
index e7fdc5a..69db052 100644
--- a/core/org.eclipse.statet.rj.client/src/org/eclipse/statet/rj/server/client/RClientGraphicDummyFactory.java
+++ b/core/org.eclipse.statet.rj.client/src/org/eclipse/statet/rj/server/client/RClientGraphicDummyFactory.java
@@ -17,6 +17,7 @@
 import java.util.Collections;
 import java.util.Map;
 
+import org.eclipse.statet.jcommons.lang.NonNull;
 import org.eclipse.statet.jcommons.lang.NonNullByDefault;
 import org.eclipse.statet.jcommons.lang.Nullable;
 
@@ -32,7 +33,7 @@
 	
 	
 	@Override
-	public Map<String, ? extends Object> getInitServerProperties() {
+	public Map<String, ? extends @NonNull Object> getInitServerProperties() {
 		return Collections.emptyMap();
 	}
 	
diff --git a/core/org.eclipse.statet.rj.client/src/org/eclipse/statet/rj/server/client/RClientGraphicFactory.java b/core/org.eclipse.statet.rj.client/src/org/eclipse/statet/rj/server/client/RClientGraphicFactory.java
index c4d5ad6..5c1b13c 100644
--- a/core/org.eclipse.statet.rj.client/src/org/eclipse/statet/rj/server/client/RClientGraphicFactory.java
+++ b/core/org.eclipse.statet.rj.client/src/org/eclipse/statet/rj/server/client/RClientGraphicFactory.java
@@ -16,6 +16,7 @@
 
 import java.util.Map;
 
+import org.eclipse.statet.jcommons.lang.NonNull;
 import org.eclipse.statet.jcommons.lang.NonNullByDefault;
 import org.eclipse.statet.jcommons.lang.Nullable;
 
@@ -64,7 +65,7 @@
 	 * 
 	 * @return a map with keys and values of the properties
 	 */
-	Map<String, ? extends Object> getInitServerProperties();
+	Map<String, ? extends @NonNull Object> getInitServerProperties();
 	
 	/**
 	 * Called if a new graphic is created in R (<code>dev.new()</code>).
diff --git a/eclient/org.eclipse.statet.rj.eclient.graphics/src/org/eclipse/statet/internal/rj/eclient/graphics/EclipseRGraphicFactory.java b/eclient/org.eclipse.statet.rj.eclient.graphics/src/org/eclipse/statet/internal/rj/eclient/graphics/EclipseRGraphicFactory.java
index 88f118b..834187f 100644
--- a/eclient/org.eclipse.statet.rj.eclient.graphics/src/org/eclipse/statet/internal/rj/eclient/graphics/EclipseRGraphicFactory.java
+++ b/eclient/org.eclipse.statet.rj.eclient.graphics/src/org/eclipse/statet/internal/rj/eclient/graphics/EclipseRGraphicFactory.java
@@ -28,6 +28,7 @@
 import org.eclipse.statet.jcommons.collections.CopyOnWriteIdentityListSet;
 import org.eclipse.statet.jcommons.collections.ImIdentityList;
 import org.eclipse.statet.jcommons.collections.ImList;
+import org.eclipse.statet.jcommons.lang.NonNull;
 import org.eclipse.statet.jcommons.lang.NonNullByDefault;
 import org.eclipse.statet.jcommons.lang.Nullable;
 
@@ -181,7 +182,7 @@
 	
 	
 	@Override
-	public Map<String, ? extends Object> getInitServerProperties() {
+	public Map<String, ? extends @NonNull Object> getInitServerProperties() {
 		final Map<String, Object> map= new HashMap<>();
 		final IPreferencesService preferences= Platform.getPreferencesService();
 		final AtomicReference<double @Nullable []> dpi= new AtomicReference<>();