gh-101992: update plistlib examples to be runnable (GH-101994)


* gh-101992: update plistlib examples to be runnable

* Update Doc/library/plistlib.rst

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(cherry picked from commit a1723caabfcdca5d675c4cb04554fb04c7edf601)

Co-authored-by: Dustin Rodrigues <dust.rod@gmail.com>
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
1 file changed