* Make sonokai palette perfectfully faithful
* Amend theme to better match original sonokai
Changes based on the following references:
(1) https://www.sainnhe.dev/post/contributing-guide/#sonokai
(2) https://github.com/sainnhe/sonokai/blob/master/colors/sonokai.vim
* Make constants white (1)
* Make builtin variables purple (1)
* Make members orange (1)
* Make labels red (2)
* Make operators red (1)
* Make all punctuation grey (2)
* Make builtin functions and macros green (2)
* Make diff delta blue (2)
* Make cursor match bg4 (2)
* Make visible whitespace bg4 (2)
* Make Sonokai special punctuation yellow
Without styling the primary and secondary selections differently, it's
impossible to tell them apart when cycling through selections.
Make the primary selection slightly brighter and secondary selections
slightly paler.
