String Attribute Renderer called for all text - not just attributes

In version 3 we could code so that an `AttributeRenderer` applied to `String.class` was only called for attributes set onto the template. We are trying to create the same behaviour with version 4. However, the `AttributeRenderer` seems to be called now for all text in the file.

We are unsure if this is a bug or we are making the wrong assumption

See test below to reproduce:

``` java

import static org.junit.Assert.fail;

import java.util.Locale;

import org.junit.Test;
import org.stringtemplate.v4.AttributeRenderer;
import org.stringtemplate.v4.ST;
import org.stringtemplate.v4.STGroupString;

public class StringTemplateRenderDoesNotGetAppliedToWholeStringTemplateTest {
@Test
public void rendererNotCalledWhenNoAttributesSet() {
STGroupString group = new STGroupString("stringTemplateWithNoAttributes() ::= << 1 >>");
group.registerRenderer(String.class, new AttributeRenderer() {

@Override
public String toString(Object o, String formatString, Locale locale) {
fail("The renderer must not get called. Object passed in was '" + o.toString() + "'");
throw new UnsupportedOperationException();
}
});
ST template = group.getInstanceOf("stringTemplateWithNoAttributes");
template.render();
}
}
```