Method getMutableArray

Fleece/Mutable/HeapArray.cc:110–112

    }

    MutableArray* HeapArray::getMutableArray(uint32_t i)  {
        return (MutableArray*)asValue(getMutable(i, internal::kArrayTag));
    }

    /** Promotes a Dict item to a HeapDict (in place) and returns it.
     Or if the item is already a HeapDict, just returns it. Else returns null. */