iOS: fix application hangs when opening keyboard

QIOSInputContext controls QUIViews first responder status
based on whether or not the keyboard should be open.
But since QGuiApplication updates focusObject before
focusWindow (when e.g a popup closes), we sometimes ended up
activating the old window upon a call to becomeFirstResponder.
This in turn led the application to hang because of
recursive dependencies in qioscontext when the focus window
changed.

So the solution for now is to avoid activating the window
when the view becomes first responder. This should be
fine since we now activate the window from
QIOSWindow::requestActivateWindow (ref: 6272a816d1)

Task-number: QTBUG-35340
Change-Id: I3068c14fec18d84d4b0b348a043c4c054e366c75
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>
qdoc: Replaced hard-coded href with computed href

For enum types that have QFlags versions, qdoc was
outputting the documentation with a hard-coded link
to qflags.html, which only workjed in the single
directory mode. When qdoc outputs modular documentation,
the href for the link should be "../qtcore/qflags.html" .
Now qdoc computes this href correctly before it writes
the docs. The href is no longer hard-coded.

Task-number: QTBUG-35209
Change-Id: Ibdf5b11dbd063726eb77048de78f8874c65752ca
Reviewed-by: Topi Reiniö <topi.reinio@digia.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>