Corrects documentation around JSONV_STRING_REF_TYPE and adds JSONV_STRING_REF_USE_STD.
Corrects documentation around JSONV_STRING_REF_TYPE and adds JSONV_STRING_REF_USE_STD.

venediktov/json-voorhees,venediktov/json-voorhees,tgockel/json-voorhees,respu/json-voorhees,respu/json-voorhees,tgockel/json-voorhees