`norvigs-lispy`: translate "Exemplos" to PT

[ramalho]

Document to translate:

https://github.com/fluentpython/lispy/blob/main/workshops/pythonbrasil2021/norvigs-lispy.ipynb

NOTE: User-defined identifiers in the Scheme source code should be translated as well, with some exceptions such as the name quicksort which is a proper noun.

Examples: factorial-iter to fatorial-iter, product to produto, good-enough? to próximo? etc.

To look up or propose a standard PT-BR translation to a specific term, please read and submit improvements to GLOSSÁRIO.md.