ac_jsonw: Change some types
ac_jsonw: Change some types

Change some unsigned char to char to match that they are operating on a
char *.

Change an int to unsigned int as it is never negative.

Signed-off-by: Andrew Clayton <02e0a999c50b1f88df7a8f5a04e1b76b35ea6a88@digital-domain.net>

ac000/libac