doc: Let's suggest GNU guidelines for bit checking.
doc: Let's suggest GNU guidelines for bit checking.

--

While educating students we can also get them to use useful habits, in
particular to parenthese bit tests.

Signed-off-by: Werner Koch <13bd1fc5137f503b0a8355ad400e7a87ebb45b25@gnupg.org>

gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme