Update keywords.txt with additional chipsets (#854)
Update keywords.txt with additional chipsets (#854)

* Alphabetize chipset section -- no content changes this commit.

* Remove duplicate definition of LPD6803

* Add PL9823 to chipset keyword literals

* Add a dozen more missing chipsets as LITERAL1:
* APA106
* DOTSTAR
* GW6205_400
* LPD1886_8BIT
* PIXIE
* SK6812
* SK6822
* SK9822
* TM1812
* UCS1904
* UCS2903
* WS2852

FastLED/FastLED,FastLED/FastLED,FastLED/FastLED,PaulStoffregen/FastLED,FastLED/FastLED,PaulStoffregen/FastLED,PaulStoffregen/FastLED