Update transform-checkpoints.md

[stefnestor]

Summary

👋 adds @prwhelan's feedback that

if the search is in progress and the frequency triggers the next checkpoint, that checkpoint will abort without searching and try again after the set frequency.

As not found yet on How checkpoints work nor sub-troubleshooting page Performance considerations.

Generative AI disclosure

1. Did you use a generative AI (GenAI) tool to assist in creating this contribution?

• Yes
• No

[github-actions]

Vale Linting Results

Summary: 3 suggestions found

💡 Suggestions (3)

File	Line	Rule	Message
explore-analyze/transforms/transform-checkpoints.md	22	Elastic.WordChoice	Consider using 'efficient' instead of 'simple', unless the term is in the UI.
explore-analyze/transforms/transform-checkpoints.md	22	Elastic.FutureTense	'will abort' might be in future tense. Write in the present tense to describe the state of the product as it is now.
explore-analyze/transforms/transform-checkpoints.md	22	Elastic.WordChoice	Consider using 'stop, cancel, end' instead of 'abort', unless the term is in the UI.

[github-actions]

🔍 Preview links for changed docs

• explore-analyze/transforms/transform-checkpoints.md

[leemthompo]

Thank you!