Replace QLatin1String with QStringLiteral

[iamthesenate1]

Output of clazy with CLAZY_CHECKS="qstring-allocations".

I've seen that opinions are divided about which one is better.
From my point of view, if this PR is merged, good. If not, also good.

[tsujan]

Personally, I think QStringLiteral is better in these places.

I've seen that opinions are divided about which one is better.

Yes, I've noticed it too.

Contrary to what Qt doc implies, I've seen no tangible gain in using either of them instead of QString::QString(const char *str) for (tens of) thousands of strings (while I've seen big gains in quite different things, about which Qt doc is silent).

[tsujan]

On second thought and apart from personal opinions (including mine), if we want to follow Qt doc, we shouldn't change all of these cases. According to Qt doc:

Note: QLatin1String can still be more efficient than QStringLiteral when the string is passed
to a function that has an overload taking QLatin1String and this overload avoids conversion to QString.

QString::operator=, QString::operator== and QString::operator+= are among those overloads.

But, for example, QSettings::setValue doesn't have such an overload and QStringLiteral seems a better choice for it.

All in all, changes may be made but more carefully.

[iamthesenate1]

I might check for such cases later. For now, I'm very busy and I regard these changes as a pretty low priority.

[tsujan]

Take your time. There's no rush at all.