abusing ? : seems unnecessary
if m_stops empty -> just return false
then try find -> judge if the term can be found (result of find is not the end of m_stops)
At ~200 lines below, `it` get reused and shadowed in a for loop `QStringList::iterator it`.
Eliminate it completely. If we use C++20, we can just std::set::contains()
shenleban tongying