Update transaction-overview.md

[cfzjywxk]

update the description for transaction memory usage

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[qiancai]

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/merge

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Commit hash: e5c33b5

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #7643.

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #7645.

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #7646.

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #7647.