fix: markdown-viewer dom mount issues and add toc to article

[qiniu-prow[bot]]

@Kasey0727: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
community-pull-preview-environment-test	542615b955e177c22217a2ad0cff6f37c2c49177	link	true	/test community-pull-preview-environment-test

Full PR test history. Your PR dashboard.

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository. I understand the commands that are listed [here](https://go.k8s.io/bot-commands).

[IRONICBo]

Please fix conflicts.

[qiniu-x[bot]]

[Git-flow] Hi @Kasey0727, There are some suggestions for your information:

---

Rebase suggestions

• Following commits have duplicated messages

fix: markdown-viewer dom mount issues

fix: markdown-viewer dom mount issues

Which seems insignificant, recommend to use git rebase command to reorganize your PR.

For other git-flow instructions, recommend refer to these examples.

If you have any questions about this comment, feel free to raise an issue here: - **https://github.com/qiniu/reviewbot**

[Kasey0727]

article without toc:

article with toc:

[qiniu-ci]

The PR environment is ready, please check the PR environment

[Attention]: This environment will be automatically cleaned up after 6 hours, please make sure to test it in time. If you have any questions, please contact the author of the PR or the community team.