docs: pt_BR: Add initial Portuguese translation

docs: pt_BR: Add initial Portuguese translation

Introduce the initial Portuguese (Brazilian) translation
for the Linux kernel documentation (HOWTO document). It establishes
the directory structure for the pt_BR locale and adds the official
entry for the pt_BR maintainer in the MAINTAINERS file.

Additionally, this version adds pt_BR support to the documentation
build script (Documentation/sphinx/translations.py) to ensure proper
rendering and fixes the documentation hierarchy to avoid orphan file
warnings.

Signed-off-by: Daniel Pereira <danielmaraboo@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
[jc: fix duplicate process_howto label]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260204113210.185221-1-danielmaraboo@gmail.com>