docs: nordic_nrf: Fix notes and use a better syntax

Fix indentation of notes appearing inside the precending code-block.
Use the .. note:: syntax to have note included in the proper note
highlighting.

Change-Id: Iafe7509a2280d2f6063fee35949a464636ce6a86
Signed-off-by: Joakim Andersson <joakim.andersson@nordicsemi.no>
2 files changed