Could not use Chinese input method for searching on showcase

### Have you read the Contributing Guidelines on issues?

- [X] I have read the [Contributing Guidelines on issues](https://github.com/facebook/docusaurus/blob/main/CONTRIBUTING.md#issues).

### Prerequisites

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

### Description

Using a Chinese input method in the search field of the [showcase](https://docusaurus.io/showcase) will result in incorrect text output and prevent the search function from operating properly.

### Reproducible demo

_No response_

### Steps to reproduce

1. open website https://docusaurus.io/showcase
2. Seach for site name with Input Method

### Expected behavior

After selecting a candidate term, the corresponding Chinese characters will appear in the search box.

### Actual behavior

After selecting a candidate term, nothing appears in the search box.

### Your environment

- Public source code:
- Public site URL: https://docusaurus.io/showcase
- Docusaurus version used:
- Environment name and version (e.g. Chrome 89, Node.js 16.4):
- Operating system and version (e.g. Ubuntu 20.04.2 LTS):

### Self-service

- [ ] I'd be willing to fix this bug myself.