<tr> tag with class="header" displayed incorrectly

[ytf4425]

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Issue Checklist

• I am using the latest version of NexT.
• I have read the relevant documents of Hexo and NexT.
• I have reviewed the latest Roadmap on GitHub and searched for current issues, which does not help me.

---

Expected behavior

The following normal table will be rendered to this html code by hexo-renderer-pandoc.

| A| B |
| :-: | :-: |
|A1| B1|
|A2| B2|

...

|A3| B3|

<div class="table-container"><table>
<colgroup>
<col style="width: 16%">
<col style="width: 83%">
</colgroup>
<thead>
<tr class="header">
<th style="text-align: center;">A</th>
<th style="text-align: center;">B</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td style="text-align: center;"> A1</td>
<td style="text-align: center;"> B1</td>
</tr>
<tr class="even">
<td style="text-align: center;">A2</td>
<td style="text-align: center;"> B2</td>
</tr>

......

<tr class="odd">
<td style="text-align: center;">AN</td>
<td style="text-align: center;">BN</td>
</tr>
</tbody>
</table></div>

And should be displayed like this.

Actual behavior

Steps to reproduce the behavior

1. use npm to uninstall hexo-renderer-marked and install hexo-renderer-pandoc.
2. render a markdown table, then you will get the wrong display in your web page.
3. remove the class="header" in tag like the following html code, then it seems to be ok.

<div class="table-container"><table>
<colgroup>
<col style="width: 16%">
<col style="width: 83%">
</colgroup>
<thead>
<tr>
<th style="text-align: center;">A</th>
<th style="text-align: center;">B</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td style="text-align: center;"> A1</td>
<td style="text-align: center;"> B1</td>
</tr>
<tr class="even">
<td style="text-align: center;">A2</td>
<td style="text-align: center;"> B2</td>
</tr>

......

<tr class="odd">
<td style="text-align: center;">AN</td>
<td style="text-align: center;">BN</td>
</tr>
</tbody>
</table></div>

Environment Information

Node.js and NPM Information

v16.15.1
8.11.0

Package dependencies Information

hexo-site@0.0.0 C:\path\to\dir
├── @next-theme/plugins@8.15.1
├── hexo-asset-img@1.0.0
├── hexo-deployer-git@4.0.0
├── hexo-generator-archive@2.0.0
├── hexo-generator-category@2.0.0
├── hexo-generator-index@3.0.0
├── hexo-generator-tag@2.0.0
├── hexo-next-valine@2.1.0
├── hexo-renderer-ejs@2.0.0
├── hexo-renderer-pandoc@0.3.1
├── hexo-renderer-stylus@2.1.0
├── hexo-server@3.0.0
├── hexo-theme-landscape@0.0.3
├── hexo-theme-next@8.15.1
└── hexo@7.0.0-rc1

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