[Doc] Various fixes

[riedgar-ms]

Trying to improve the docs:

• Get code blocks working correctly for the guidance.json() functionality
• Add some code blocks to gen() and select()
• Add code blocks to the roles

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 61.82%. Comparing base (7216886) to head (b859431).

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #833 +/- ## ========================================== + Coverage 59.60% 61.82% +2.22% ========================================== Files 58 58 Lines 4317 4317 ========================================== + Hits 2573 2669 +96 + Misses 1744 1648 -96 ```

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[Harsha-Nori]

These changes look great to me :)