system-variables: fix a typo for "GROUP"

[qiancai]

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What is the related PR or file link(s)?

• This PR is translated from: system-variables: fix a typo for "GROUP" docs-cn#14471
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Do your changes match any of the following descriptions?

• Delete files
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• Might cause conflicts after applied to another branch

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-07-12 02:43:18.408105295 +0000 UTC m=+472690.178444008: ☑️ agreed by Oreoxmt.

[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-6.1: #14199.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.5: #14200.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.0: #14201.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #14202.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.2: #14203.