dev, v3.0, v2.1: add safe-mode config in binlog reparo doc

[junlan-zhang]

What is changed, added or deleted?

• Add a safe-mode config in binlog reparo doc

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

pingcap/docs-cn#1558

Which version does your change affect?

dev, v3.0, v2.1

Checklist

• Add a new file to TOC.md
• No Tab spaces anywhere
• Leave a blank line both before and after a code block
• Keep the first level heading consistent with title in metadata
• Use four spaces for each level of indentation except that in TOC.md

[TomShawn]

Please also apply these changes to the dev and v3.0 versions.

[lilin90]

@ericsyh PTAL

[TomShawn]

LGTM

[CLAassistant]

All committers have signed the CLA.

[CLAassistant]

Thank you for your submission, we really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

✅ juliezhang1112
❌ Julie Zhang

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[ericsyh]

LGTM

[lilin90]

@juliezhang1112 Please sign the CLA. It seems that you used two accounts to commit.

[junlan-zhang]

I create a PR just the same as this one due to the CLA error.
#1441