[SPARK-20769][DOC] Incorrect documentation for using Jupyter notebook

## What changes were proposed in this pull request?

SPARK-13973 incorrectly removed the required PYSPARK_DRIVER_PYTHON_OPTS=notebook from documentation to use pyspark with Jupyter notebook. This patch corrects the documentation error.

## How was this patch tested?

Tested invocation locally with
```bash
PYSPARK_DRIVER_PYTHON=jupyter PYSPARK_DRIVER_PYTHON_OPTS=notebook ./bin/pyspark
```

Author: Andrew Ray <ray.andrew@gmail.com>

Closes #18001 from aray/patch-1.

docs/rdd-programming-guide.md

@@ -247,7 +247,7 @@ $ PYSPARK_DRIVER_PYTHON=ipython ./bin/pyspark
 To use the Jupyter notebook (previously known as the IPython notebook),
 
 {% highlight bash %}
-$ PYSPARK_DRIVER_PYTHON=jupyter ./bin/pyspark
+$ PYSPARK_DRIVER_PYTHON=jupyter PYSPARK_DRIVER_PYTHON_OPTS=notebook ./bin/pyspark
 {% endhighlight %}
 
 You can customize the `ipython` or `jupyter` commands by setting `PYSPARK_DRIVER_PYTHON_OPTS`.