v7.1: remove the support info of optimize-filters-for-memory

[qiancai]

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• master (the latest development version)
• v7.2 (TiDB 7.2 versions)
• v7.1 (TiDB 7.1 versions)
• v7.0 (TiDB 7.0 versions)
• v6.6 (TiDB 6.6 versions)
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• v6.1 (TiDB 6.1 versions)
• v5.4 (TiDB 5.4 versions)
• v5.3 (TiDB 5.3 versions)
• v5.2 (TiDB 5.2 versions)
• v5.1 (TiDB 5.1 versions)
• v5.0 (TiDB 5.0 versions)

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

• This PR is translated from: v7.1: remove the support info of optimize-filters-for-memory docs-cn#14275
• Other reference link(s):

Do your changes match any of the following descriptions?

• Delete files
• Change aliases
• Need modification after applied to another branch
• Might cause conflicts after applied to another branch

[Oreoxmt]

/lgtm

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-06-19 02:47:54.020635623 +0000 UTC m=+572270.435239686: ☑️ agreed by Oreoxmt.

[qiancai]

/approve

[ti-chi-bot]

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