docs/devel/reset: Fix minor grammatical error

Fix a minor grammatical error in the reset documentation:
a couple of missing words and a singular/plural swap.

Signed-off-by: Axel Heider <axel.heider@codasip.com>
Message-id: 173006362760.28451.11319467059840843945-1@git.sr.ht
[PMM: squashed two patches into one, tweaked commit message]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
1 file changed