This allows for instance to show the current UI language in the UI,
or to load additional translations that match the .qm file by other
means.
This is especially useful in the case of QTranslator::load(QLocale(),
...), in which case different language and country combinations might
be tried.
Another option is to inspect the file name via QTranslator::filePath();
however, this is more error-prone, and might also miss information
(if the .qm file name doesn't have a country suffix, or no suffix at
all).
Change-Id: I6f565d53d8f50e21241ccae6c4de264747ac8f81
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>