chore(samples): fix region tag import

[FrodoTheTrue]

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Fixes #140 🦕

[snippet-bot]

Here is the summary of changes.

You are about to add 4 region tags.

• samples/snippets/sample_start_stop.py:21, tag compute_start_instance
• samples/snippets/sample_start_stop.py:22, tag compute_start_enc_instance
• samples/snippets/sample_start_stop.py:23, tag compute_stop_instance
• samples/snippets/sample_start_stop.py:24, tag compute_reset_instance

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