Documentation Error in validation-chain.md

[BradleyLi]

Describe the bug

In the line 57 of the file "docs/api/validator/validation-chain.md", there is an extra closing parenthesis.

Expected behavior

The number of opening and closing parentheses should match with each other.

Current behavior

The number of opening and closing parentheses do not match. Here is what it currently looks like on the website URL "https://express-validator.github.io/docs/api/validation-chain/":

Environment:

• Express-validator version: 7.0.1
• Express version: N/A(Express is not included in package.json as a dependency)
• Node.js version: >= 8.0.0