This commit uses the new .. zephyr:code-sample-category directive to
categorize code samples across the tree.
Updates existing legacy references to manually defined targets to now
use :zephyr:code-sample-category: role instead.
Signed-off-by: Benjamin Cabé <benjamin@zephyrproject.org>
Print whether or not the code is actually in usermode.
Fail the execution with an assertion if not the case.
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>