QTextDocument should render <hr> in WindowText colour

Problem with QTextDocument.

If the user sets a "Dark Theme", then <hr> isn't visible because the current default rendering is in a "dark" colour (I think Black).   When a Dark Theme is active this means the <hr> is invisible.

Instead it should be rendered by default in the colour returned by:

palette().color(QPalette::ColorRole::WindowText).name()

so it will be visible regardless of the chosen theme.

If of course the user sets a background-color in the style for the <hr> that should be used instead.  I've worked round this by using (e.g.):

insertHtml("<hr style=\"background-color:" + palette().color(QPalette::ColorRole::WindowText).name() + "\">");

David