Print Dialog Stalling on Chrome if no footer icons are specified.

[kenkaijie]

Thank you for this theme!

I have encountered an issue when trying to print some documentation via Chrome.

The issue occurs when conf.py is not set up with footer_icons in html_theme_options. If no icon is configured, it seems the presence of the <div class="icons></div> empty nested flex box causes the print dialog to have a very large page count.

This is related (in symptom) to #358.

[pradyunsg]

Thanks for a clear description on this @kenkaijie! ^>^

308cf67 should resolve this.