Port from qAsConst() to std::as_const()

We've been requiring C++17 since Qt 6.0, and our qAsConst use finally
starts to bother us (QTBUG-99313), so time to port away from it
now.

Since qAsConst has exactly the same semantics as std::as_const (down
to rvalue treatment, constexpr'ness and noexcept'ness), there's really
nothing more to it than a global search-and-replace.

Task-number: QTBUG-99313
Change-Id: I88edd91395849574436299b8badda21bb93bea39
Reviewed-by: hjk <hjk@qt.io>

src/plugins/texteditor/formattexteditor.cpp

@@ -240,7 +240,7 @@ static void updateEditorText(QPlainTextEdit *editor, const QString &text)
                                               + absoluteVerticalCursorOffset / fontHeight);
     // Restore folded blocks
     const QTextDocument *doc = editor->document();
-    for (int blockId : qAsConst(foldedBlocks)) {
+    for (int blockId : std::as_const(foldedBlocks)) {
         const QTextBlock block = doc->findBlockByNumber(qMax(0, blockId));
         if (block.isValid())
             TextDocumentLayout::doFoldOrUnfold(block, false);