Port from qAsConst() to std::as_const()

We've been requiring C++17 since Qt 6.0, and our qAsConst use finally
starts to bother us (QTBUG-99313), so time to port away from it
now.

Since qAsConst has exactly the same semantics as std::as_const (down
to rvalue treatment, constexpr'ness and noexcept'ness), there's really
nothing more to it than a global search-and-replace.

Task-number: QTBUG-99313
Change-Id: I88edd91395849574436299b8badda21bb93bea39
Reviewed-by: hjk <hjk@qt.io>

src/plugins/projectexplorer/journaldwatcher.cpp

@@ -190,7 +190,7 @@ void JournaldWatcher::handleEntry()
         if (logEntry.isEmpty())
             break;
 
-        for (const JournaldWatcherPrivate::SubscriberInformation &info: qAsConst(d->m_subscriptions))
+        for (const JournaldWatcherPrivate::SubscriberInformation &info: std::as_const(d->m_subscriptions))
             info.subscription(logEntry);
     }
 }