tidb config: add txn-entry-size-limit (#5158)

[ti-srebot]

cherry-pick #5158 to release-4.0
You can switch your code base to this Pull Request by using git-extras:

# In docs-cn repo:
git pr https://github.com/pingcap/docs-cn/pull/5319

After apply modifications, you can push your change to this PR via:

git push git@github.com:ti-srebot/docs-cn.git pr/5319:release-4.0-309bba59e425

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Signed-off-by: youjiali1995 zlwgx1023@gmail.com

What is changed, added or deleted? (Required)

Add a new configuration. It's introduced in v5.0 and v4.0.10. https://github.com/pingcap/tidb/pull/21843/files

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

• master (the latest development version)
• v4.0 (TiDB 4.0 versions) Follow UP: CP to release-4.0 after v4.0.10 is released
• v3.1 (TiDB 3.1 versions)
• v3.0 (TiDB 3.0 versions)
• v2.1 (TiDB 2.1 versions)

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

• This PR is translated from:
• 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

[ti-srebot]

@youjiali1995 you're already a collaborator in bot's repo.