doc: Reword and reformat a sentence on review time
doc: Reword and reformat a sentence on review time

Move the sentence to the end of the section on labels applicable to
PRs only, reword it and convert to a note, indicating that the note
is for all labels in this section.

Signed-off-by: Aleksandar Markovic <8084fc9c6866c5a3f7ad74f44ee247322c1b4f7a@gmail.com>

finikorg/zephyr,galak/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr