Delete unnecessary override.

PiperOrigin-RevId: 910283008

Author: Jesse-Good

java/src/com/google/template/soy/soytree/ExternNode.java

@@ -28,10 +28,8 @@
 import com.google.template.soy.soytree.defn.TemplateParam;
 import com.google.template.soy.types.FunctionType;
 import com.google.template.soy.types.ast.FunctionTypeNode;
-import com.google.template.soy.types.ast.TypeNode;
 import com.google.template.soy.types.ast.TypesHolderNode;
 import java.util.Optional;
-import java.util.stream.Stream;
 
 /**
  * Node representing a 'extern' statement with js/java implementations. TODO(b/191090743) Handle the
@@ -110,15 +108,11 @@ public boolean isJavaImplAsync() {
     return getJavaImpl().map(j -> j.isAsync()).orElse(false);
   }
 
+  @Override
   public FunctionTypeNode getTypeNode() {
     return typeNode;
   }
 
-  @Override
-  public Stream<TypeNode> getTypeNodes() {
-    return Stream.of(typeNode);
-  }
-
   @Override
   public ImmutableList<CommandTagAttribute> getAttributes() {
     return ImmutableList.of();