These were marked as translatable in DolphinWX but not DolphinQt,
yet both DolphinWX and DolphinQt tried to fetch translations for them.
This meant that translations worked in both DolphinWX and DolphinQt
back when DolphinWX existed, but that translations stopped working
in DolphinQt once DolphinWX was removed (because the removal of
DolphinWX triggered the removal of the strings from the .po files).
QStringLiterals generate a buffer so that during runtime there's very
little cost to constructing a QString. However, this also means that
duplicated strings cannot be optimized out into a single entry that gets
referenced everywhere, taking up space in the binary.
Rather than use QStringLiteral(""), we can just use QString{} (the
default constructor) to signify the empty string. This gets rid of an
unnecessary string buffer from being created, saving a tiny bit of
space.
While we're at it, we can just use the character overloads of particular
functions when they're available instead of using a QString overload.
The characters in this case are Latin-1 to begin with, so we can just
specify the characters as QLatin1Char instances to use those overloads.
These will automatically convert to QChar if needed, so this is safe.
