[DOCS] MonsterUI concise guide section needs to be improved

[Isaac-Flath]

Issue Type

• [x] Existing documentation (e.g. typos, errors, outdated information)
• [ ] Suggest new documentation that is currently missing

Current Behavior or Documentation Gaps

The concise guide section on MonsterUI does not include the core information about using MonsterUI, and the API list is missing enum members which is critical for LLMs and they hallucinate otherwise. Key areas include:

• Layout Helpers
• Typography (markdown and semantic)
• Forms
• Enum styling usage

Suggested Improvement or New Documentation Content
See PR

Relevant Links

https://github.com/AnswerDotAI/fasthtml/blob/main/nbs/ref/concise_guide.ipynb

Confirmation
Please confirm the following:

• [x] I have checked the existing issues and pull requests to ensure this documentation issue hasn't been reported before.
• [x] I have read the project's documentation and am confident this issue or suggestion is valid.