Previous API were using an internal vector to store the suggestions search
results.
The new API takes a vector as out argument. So user can call the functions
without having to protect the search.
We should change the android API to reflect the change but it is a bit
more complex to do at JNI level. As android do not call it multithreaded
we are safe for now. And we need the new API asap for kiwix-desktop.
So we keep the same API on android for now, the new api will be made
in next version.