Specify what Unicode general categories str.isalnum refers to

[slateny]

Per this comment, specifying the aggregated categories of str.isalnum could help with clarity.

[StanFromIreland]

In my opinion, I think the current docs are fine. This information is already provided in the doc for isalpha(), isdecimal(), isdigit(), and isnumeric() reproducing it will be duplicative.