fix: showInMentions attribute is now serialized correctly (#2137)

This was an error introduced in ec94869. Instead of the
Qt::CheckStateRole, which stores the state represented in the table
view, the Qt::DisplayRole was used. As per [1], this always returns
`false` in our use case.

[1]: https://doc.qt.io/qt-5/qvariant.html#toBool

src/controllers/highlights/HighlightModel.cpp

@@ -25,7 +25,7 @@ HighlightPhrase HighlightModel::getItemFromRow(
 
     return HighlightPhrase{
         row[Column::Pattern]->data(Qt::DisplayRole).toString(),
-        row[Column::ShowInMentions]->data(Qt::DisplayRole).toBool(),
+        row[Column::ShowInMentions]->data(Qt::CheckStateRole).toBool(),
         row[Column::FlashTaskbar]->data(Qt::CheckStateRole).toBool(),
         row[Column::PlaySound]->data(Qt::CheckStateRole).toBool(),
         row[Column::UseRegex]->data(Qt::CheckStateRole).toBool(),