code: public void writeBindingContextJavadoc(SourceWriter writer, Context bindingContext,
        Key<?> key) {
      writeBindingContextJavadoc(writer, bindingContext,
          "Binding for " + key.getTypeLiteral() + " declared at:");
    }
docs: Write the Javadoc for the binding of a particular key, showing the context
  of the binding.
  
  @param key The bound key.
  @param writer The writer to use to write this comment.
  @param bindingContext The context of the binding.