* docs: added fiddle support for code samples in quick start guide and features
* docs: removed excessive fiddle links for not final steps
* docs: added eof newlines to fiddle examples
* docs: reworked fiddle examples to be more self-sufficient
* docs: reworked fiddle examples according to mentions
* docs: changed http to https in the offscreen rendering fiddle
* docs: fix recent documents fiddle to be more consistent
* docs: revised dark mode page
* docs: fixed lint errors in dark mode page
* docs: fixed mentions, revised doc structure in the dark mode feature page
* docs: fixed mentions, made all the steps more verbose in the dark mode feature page
