doc: minor comment corrections and additions
doc: minor comment corrections and additions

Signed-off-by: Sebastien Awwad <3db59c6db3a806262760013e1ae477b12a72032f@gmail.com>
Signed-off-by: Lukas Puehringer <42074506cdafde8c7d787023901a1714526f0a58@nyu.edu>

secure-systems-lab/securesystemslib,secure-systems-lab/securesystemslib