Misspelled expression in the PyQt6 tutorial

[JCionx]

In the Create your first app with PyQt6 tutorial there's a misspelled Python expression in the Stepping through the code.

This is the sentence that contains the misspelled expression:

Next we create an instance of QApplication, passing in sys.arg, which is Python list containing the command line arguments passed to the application.

In this sentence, the sys.arg expression is incorrect, and should instead be sys.argv.

Here is a screenshot that shows the sentence where the expression is:

Thanks for the great tutorial! Just wanted to point out a small typo.

[lpozo]

https://github.com/pythonguis/pythonguis/pull/176