[WIP]: add v8.5.0 release notes

[qiancai]

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What is changed, added or deleted? (Required)

Which TiDB version(s) do your changes apply to? (Required)

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For details, see tips for choosing the affected versions.

• master (the latest development version)
• v8.4 (TiDB 8.4 versions)
• v8.3 (TiDB 8.3 versions)
• v8.2 (TiDB 8.2 versions)
• v8.1 (TiDB 8.1 versions)
• v7.5 (TiDB 7.5 versions)
• v7.1 (TiDB 7.1 versions)
• v6.5 (TiDB 6.5 versions)
• v6.1 (TiDB 6.1 versions)
• v5.4 (TiDB 5.4 versions)
• v5.3 (TiDB 5.3 versions)

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

• This PR is translated from: [WIP]: add v8.5.0 release notes docs#19336
• Other reference link(s):

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

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[YangKeao]

LGTM

[ti-chi-bot]

@YangKeao: adding LGTM is restricted to approvers and reviewers in OWNERS files.

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LGTM

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[Frank945946]

Suggested change

	* Schema 缓存内存上限功能成为正式功能（GA），减少了大规模数据场景的内存占用 [#50959](https://github.com/pingcap/tidb/issues/50959) @[tiancaiamao](https://github.com/tiancaiamao) @[wjhuang2016](https://github.com/wjhuang2016) @[gmhdbjd](https://github.com/gmhdbjd) @[tangenta](https://github.com/tangenta) tw@hfxsd <!--1976-->
	* Schema 缓存内存上限功能成为正式功能（GA），可以在集群拥有数十万甚至百万个数据库或表的场景中减少内存的使用。 [#50959](https://github.com/pingcap/tidb/issues/50959) @[tiancaiamao](https://github.com/tiancaiamao) @[wjhuang2016](https://github.com/wjhuang2016) @[gmhdbjd](https://github.com/gmhdbjd) @[tangenta](https://github.com/tangenta) tw@hfxsd <!--1976-->

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-12-10 07:12:52.61774206 +0000 UTC m=+336162.706544604: ☑️ agreed by hfxsd.
• 2024-12-11 03:42:28.560284437 +0000 UTC m=+409938.649086979: ☑️ agreed by Oreoxmt.

[lilin90]

/lgtm

[ti-chi-bot]

@BornChanger: adding LGTM is restricted to approvers and reviewers in OWNERS files.

In response to this:

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[Oreoxmt]

Suggested change

	* TiKV 支持 MVCC 内存引擎 (In-memory Engine, IME)，可加速需要扫描大量 MVCC 历史版本的查询 [#16141](https://github.com/tikv/tikv/issues/16141) [@SpadeA-Tang](https://github.com/SpadeA-Tang) [@glorv](https://github.com/glorv) [@overvenus](https://github.com/overvenus)
	* TiKV 支持 MVCC 内存引擎 (In-memory Engine, IME)，可加速需要扫描大量 MVCC 历史版本的查询 [#16141](https://github.com/tikv/tikv/issues/16141) @[SpadeA-Tang](https://github.com/SpadeA-Tang) @[glorv](https://github.com/glorv) @[overvenus](https://github.com/overvenus)