Add missing overrider

Author: Mitja Leino

src/main/java/com/redhat/devtools/lsp4ij/settings/ui/ServerNameWidget.java

@@ -38,6 +38,7 @@ public void validateInput() {
         }
     }
 
+    @Override
     public ValidationInfo getValidationInfo() {
         if (isValid()) {
             return null;