[Docs-UI] Investigate Improving Accessibility Scores for Code Samples

We received some feedback on Discord from a user about the documentation: 

https://discord.com/channels/915294689681362954/1182978471119552512/1218251547343851552 

They provided the following image, from an accessibility checker, showing how poor the contrast is between the colors we're currently using with highlight.js in our code samples: 

Let's use this opportunity to investigate what we can do to improve contrast and legibility for code samples in the documentation UI.