The Qt Widgets Application example was moved to manual tests,
and no longer contains the snippet identifiers. Fix \snippet
and \quotefile commands to quote similar code snippets from
other examples or snippet files.
Fix also the following documentation warnings:
* No such parameter 'parsingMode' in QUrl::fromEncoded()
* Missing image: rsslisting.cpp
Pick-to: 6.6 6.5
Change-Id: Ibc989e83abc49837db08628facaf8e5f72b2f123
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
17ddf2a6a5