Fix contrast ratio for guide syntax hilighting [ci-skip]
Fix contrast ratio for guide syntax hilighting [ci-skip]

The theme used for syntax hilighting has a number of colors that
do not meet the 4.5:1 minimum contrast ratio of the Web Content
Accessibility Guidelines (WCAG) 2.1 standard.

All colors that were below 4.5:1 on a background of #eeeeee have
been adjusted to be at or slightly above 4.5:1 using tweaked
versions of the tools in this repository:

https://github.com/mpchadwick/pygments-high-contrast-stylesheets/

esparta/rails,MSP-Greg/rails,yawboakye/rails,georgeclaghorn/rails,georgeclaghorn/rails,Edouard-chin/rails,rails/rails,kddeisz/rails,kddeisz/rails,MSP-Greg/rails,Stellenticket/rails,MSP-Greg/rails,Envek/rails,kmcphillips/rails,yahonda/rails,yawboakye/rails,rails/rails,rails/rails,esparta/rails,yawboakye/rails,Erol/rails,Vasfed/rails,lcreid/rails,Erol/rails,Edouard-chin/rails,Stellenticket/rails,BlakeWilliams/rails,kmcphillips/rails,kmcphillips/rails,Envek/rails,Vasfed/rails,BlakeWilliams/rails,Vasfed/rails,kmcphillips/rails,yawboakye/rails,Stellenticket/rails,yahonda/rails,esparta/rails,BlakeWilliams/rails,esparta/rails,rails/rails,Edouard-chin/rails,Stellenticket/rails,lcreid/rails,kddeisz/rails,lcreid/rails,georgeclaghorn/rails,Envek/rails,Envek/rails,Edouard-chin/rails,Vasfed/rails,Erol/rails,Erol/rails,kddeisz/rails,yahonda/rails,lcreid/rails,MSP-Greg/rails,BlakeWilliams/rails,georgeclaghorn/rails,yahonda/rails