Missing plot in Quantile Regression example?

Should the quantile regression example in the docs here:

https://xgboost.readthedocs.io/en/latest/python/examples/quantile_regression.html

include a plot?

It looks like changing `"--plot"` to `"plot"` here might fix that.

https://github.com/dmlc/xgboost/blob/34a261669614e63c8095df1a01842e5920330b30/demo/guide-python/quantile_regression.py#L121C1-L129C24

Also, to get the code to run, I changed `args = parser.parse_args()` to `args, unknown = parser.parse_known_args()` based on this https://stackoverflow.com/a/55329134.