simple-api: reposition the prototypes in the public header
simple-api: reposition the prototypes in the public header

Move the 'multiple' variants below the single value ones.

Signed-off-by: Bartosz Golaszewski <108de5fbc428215dc26df4468b48691526611148@gmail.com>

brgl/libgpiod,brgl/libgpiod,brgl/libgpiod,brgl/libgpiod