[docs] add LLM context for style authoring

[mellyeliu]

Adding a docs section for style authoring. We should follow this up with a block for setup instructions.

This should be expanded to include:

• Documentation on APIs and API usage
• Bundler setup instructions
• ESLint fixer guide for LLMs and instructions to disallow certain CSS properties or practices (border shorthands, disalllowed properties within StyleX, prefer conditional styles over dynamic styles when possible, etc)

...etc

[henryqdineen]

Suggested change

	});
	});
	```

unclosed codeblock? would it also help to have an example of using the dynamic style?

[henryqdineen]

Suggested change

	```javascript
	```jsx

[henryqdineen]

Suggested change

	```javascript
	```jsx