pt_BR/books/porters-handbook: Sync with en_US r53598

Fix several failing strings reported by Weblate (Quality checks).

Approved by: ebrandi
Obtained from: https://weblate.eastus.cloudapp.azure.com/projects/freebsd-doc/boooks_porters-handbook/pt_BR/
Differential Revision: https://reviews.freebsd.org/D22416