br-pitr-manual: remove an unnecessary quotation mark (#19175)

[ti-chi-bot]

This is an automated cherry-pick of #19175

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[qiancai]

/approve

[ti-chi-bot]

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[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.5: #19178.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #19179.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.5: #19180.