@[example] macro within <details> tag is rendered outside of <details>

[tcNickolas]

Describe the bug
@[example] macro within <details> tag is rendered outside of <details> section, showing up even if the <details> section is collapsed.

To Reproduce

Multi-Qubit Measurements kata, exercise Multi-Qubit Measurement Outcome Probabilities II, Code-Based Solution - the code included in it is rendered outside the <details>. You can see it both in the playground and in the website.

Expected behavior

Exercise rendered within <details> tag and collapsed together with it, showing the code only when expanded.

[tcNickolas]

After an offline discussion we concluded that this is caused by the fact that all macros are treated as top-level entries, and they split the code between them into separate HTML sections, so the <\details> tag ends up in a separate section from the opening tag. This is challenging to fix, and this is used only this once (I can't think of another occurrence of this scenario in the upcoming katas either), so we agreed to do a workaround by modifying the text to discuss the code outside of the <details> tag: #1631.