Doc: Sql example Books lock rating column width

Lock the width of the rating column to prohibit the contents to escape
the bounds of the column upon resize.

Task-number: QTBUG-68652
Change-Id: I5c744833b19a8e5bcf88ef1b9ab657ac81f5aa50
Reviewed-by: Nico Vertriest <nico.vertriest@qt.io>
Reviewed-by: Topi Reiniö <topi.reinio@qt.io>

examples/sql/books/bookwindow.cpp

@@ -115,6 +115,11 @@ BookWindow::BookWindow()
     ui.genreEdit->setModelColumn(
                 model->relationModel(genreIdx)->fieldIndex("name"));
 
+    // Lock and prohibit resizing of the width of the rating column:
+    ui.bookTable->horizontalHeader()->setSectionResizeMode(
+                model->fieldIndex("rating"),
+                QHeaderView::ResizeToContents);
+
     QDataWidgetMapper *mapper = new QDataWidgetMapper(this);
     mapper->setModel(model);
     mapper->setItemDelegate(new BookDelegate(this));