Update Standard Library sys documentation

[RetiredWizard]

I noticed the Circuit Python documentation for the Standard library sys doesn't include an entry for the print_exception function and that a couple attributes which are present in Micropython but not in Circuit Python (tracebacklimit and ps1/ps2) were included in the Circuit Python documentation.

I found the sys.rst file which appears to be the documentation source so I've updated it by adding/removing the appropriate sections.

[jepler]

This is fine if it's green (I tweaked the markup so that traceback and traceback.print_exception would become hyperlinks). However, we might also just choose to remove this non-standard python extension: #9446 and should consider which to do.

[jepler]

Thanks. We need to remember to remove this in the main branch, now, but it's also nice to have the other non-applicable docs removed.

[tannewt]

Thank you! #9451 filed to remember to remove it in 10.