Never return null from Widget#getMessage since the

narrator will always dereference it, leading to a crash.

src/main/java/appeng/client/gui/widgets/SettingToggleButton.java

@@ -314,7 +314,7 @@ public class SettingToggleButton<T extends Enum<T>> extends IconButton {
 
             return name + '\n' + sb;
         }
-        return null;
+        return "";
     }
 
     public String getFillVar() {

src/main/java/appeng/client/gui/widgets/ToggleButton.java

@@ -99,7 +99,7 @@ public class ToggleButton extends Button implements ITooltip {
 
             return name + '\n' + sb;
         }
-        return null;
+        return "";
     }
 
     @Override

src/main/java/appeng/fluids/client/gui/widgets/FluidTankWidget.java

@@ -93,7 +93,7 @@ public class FluidTankWidget extends Widget implements ITooltip {
 
             return desc + "\n" + amountToText;
         }
-        return null;
+        return "";
     }
 
     @Override