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

[ericsyh]

What is changed, added or deleted?

In pingcap/tidb-binlog#652 we add a new config safe-mode in reparo, this PR this to update the reparo documents about the new config.

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

In pingcap/tidb-binlog#652.

Which version does your change affect?

Apply in dev/v3.0/v2.1

[yikeke]

Important Update: We have added a markdownlint static check in the CI check to improve the quality of our documentation, so your unclosed PR might fail the CI check now.

First, you should merge upstream master to your branch, so the upstream changes might resolve the issues found by the CI check. Then, click details beside the ci/circleci: lint — Your tests failed on CircleCI message, and you can check the details for the failure and fix all the issues in your PR. It is recommended to install "markdownlint" extension in your VS Code editor, so it will check all potential issues that fail the CI check.

@ericsyh If you have any problem with troubleshooting, please consult @yikeke for help. Thanks for your cooperation~

Ref: #1494

[WangXiangUSTC]

LGTM

[yikeke]

Please remove the hard tab in the Line 36 of the changed dev/reference/tools/tidb-binlog/reparo.md file, so your pull request can pass the CI check. Thanks~ @ericsyh

[ericsyh]

Okay, i will fix it.

[yikeke]

LGTM