Pelican 4.7.0

• Improve default theme rendering on mobile and other small screen devices (#2914)
• Add support for hidden articles (#2866)
• Improve word count behavior when generating summary CJK & other locales (#2864)
• Add progress spinner during generation (#2869) and richer logging (#2897), both via Rich
• Invoke tasks serve and livereload now auto-open a web browser pointing to the locally-served web site (#2764)
• Support some date format codes used by ISO dates (#2902)
• Document how to add a new writer (#2901)