Have you read the Contributing Guidelines on issues?

• I have read the Contributing Guidelines on issues.

Prerequisites

• I'm using the latest version of Docusaurus.
• I have tried the npm run clear or yarn clear command.
• I have tried rm -rf node_modules yarn.lock package-lock.json and re-installing packages.
• I have tried creating a repro with https://new.docusaurus.io.
• I have read the console error message carefully (if applicable).

Description

I Write a Test Case below

输入：a = "abcd", b = "cdabcdab"
输出：3
解释：a 重复叠加三遍后为 "abcdabcdabcd", 此时 b 是其子串。

<pre>
  <strong>输入：</strong>a = "abcd", b = "cdabcdab"
  <strong>输出：</strong>3
  <strong>解释：</strong>a 重复叠加三遍后为 "ab<strong>cdabcdab</strong>cd", 此时 b 是其子串。
</pre>

As we can see blow, Github shows correctly
but if this block appears in a docusaurus MarkDown file when build a website
it appears like blow

[object Object]a = "abcd", b = "cdabcdab"[object Object]3[object Object]a 重复叠加三遍后为 "ab[object Object]cd", 此时 b 是其子串。

which turns <strong> tag into [object Object]

Steps to reproduce

write a markdown file includes <strong> tag in a <pre> tag

<pre>
  <strong>输入：</strong>a = "abcd", b = "cdabcdab"
  <strong>输出：</strong>3
  <strong>解释：</strong>a 重复叠加三遍后为 "ab<strong>cdabcdab</strong>cd", 此时 b 是其子串。
</pre>

Expected behavior

Correct Content

Actual behavior

Incorrent

Your environment

• Public source code: https://github.com/DawnMagnet/algorithm-station
• Public site URL:https://dawnmagnet.github.io/algorithm-station
• Docusaurus version used: latest
• Environment name and version (e.g. Chrome 89, Node.js 16.4): nodejs 14
• Operating system and version (e.g. Ubuntu 20.04.2 LTS): travis-ci

Reproducible demo

No response

Self-service

• I'd be willing to fix this bug myself.