code: static SoyExpression accessField(
        SoyProtoType protoType, SoyExpression baseExpr, FieldAccessNode node) {
      return new AccessorGenerator(protoType, baseExpr, node).generate();
    }
docs: Returns a {@link SoyExpression} for accessing a field of a proto.
  
  @param protoType The type of the proto being accessed
  @param baseExpr The proto being accessed
  @param node The field access operation