en, zh: del tidb-cluster and tidb-backup in v1.6.0

[srstack]

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Timeline:

• 2024-06-04 06:12:52.814706391 +0000 UTC m=+3361726.571841965: ☑️ agreed by csuzhangxc.

[Oreoxmt]

@srstack Could you please confirm whether lines 180-181 need to be removed?

docs-tidb-operator/en/tidb-toolkit.md

Lines 180 to 181 in 9842802

	* `tidb-cluster`: used to deploy TiDB clusters;
	* `tidb-backup`: used to back up or restore TiDB clusters;

[csuzhangxc]

L180-L181 should be removed