Bug in matching parentheses code example from Qt Quarterly 31

On the bottom of the page

https://doc.qt.io/qt-5/qtwidgets-richtext-syntaxhighlighter-example.html

there is a link to

Qt Quarterly 31 (http://doc.qt.io/archives/qq/)

with an example code for matching parentheses with QSyntaxHighlighter. The example code contains a bug within

bool TextEdit::matchRightParenthesis(QTextBlock currentBlock, int i, int numRightParentheses)

I attach a file with a possible correction and extension of your code example - it contains some additional code, you can ignore.