parser: Correctly increment the array index counter
parser: Correctly increment the array index counter

We pass the counter to the JsonParser::array-element signal, but we
never really increment it.

frida/json-glib,ebassi/json-glib,ebassi/json-glib,frida/json-glib,ebassi/json-glib,GNOME/json-glib,GNOME/json-glib