Fix typos in Python script comment

[rkurniawati]

Hello,

Thanks for the helpful documentation on IBM watsonx.data connector!
I noticed a couple of small but potentially confusing typos in the comments, both of which are addressed by this PR.

Ruth

[Paul-Cornell]

Hello, @rkurniawati. I am happy to make these updates. For future reference, could you please provide some more information about why these are potentially confusing typos? Thanks!

[rkurniawati]

A couple of the variable names in the comment don't match the code in associated the python code. I was able to figure out with a little debugging, but initially when I followed the instructions in the WatsonX connector documentation to create a python script that uses pyiceberg to connect to the Iceberg catalog, I ran into problems because of these wrong variable names. When I saw the listed environment variables, I created a .env file using the variables in the comment, but my script didn't work because the variable names in the instructional comment don't match the code in the python code.