[TXyy2023]

The abort/unwind examples currently only print different messages based on cfg; neither one actually panics. Add a small Drop example and commands for both strategies so readers can observe cleanup during unwinding and its absence when aborting. Preserve the existing conditional-compilation examples and clarify their purpose.

Fixes #1957.

Validation:

• mdbook test (including the new should_panic example).
• Compiled and ran all three examples with both -C panic=unwind and -C panic=abort; only the unwinding panic runs the destructor, and the existing examples still exit normally.
• English, Japanese, Chinese, Spanish and Korean builds, plus the official full-tree link checker for all five outputs.
• git diff --check.

AI assistance: this change and its validation were prepared with OpenAI Codex in an automated contribution workflow.

[rustbot]

Thanks for the pull request, and welcome! The Rust Project has assigned @marioidival (or someone else) to review your changes, you should hear from them (or someone else) within the next two weeks.

Why was this reviewer chosen?

The reviewer was selected based on:

• Owners of files modified in this PR: @marioidival