docs(config): fix type of preview.allowedHosts to 'string[] | true'

[wo-o29]

Description

This PR fixes the type definition of preview.allowedHosts in the Vite documentation.
The type was incorrectly specified as string | true, but it should be string[] | true to align with the actual implementation and server.allowedHosts type.

interface CommonServerOptions {
  /**
   * The hostnames that Vite is allowed to respond to.
   * `localhost` and subdomains under `.localhost` and all IP addresses are allowed by default.
   * When using HTTPS, this check is skipped.
   *
   * If a string starts with `.`, it will allow that hostname without the `.` and all subdomains under the hostname.
   * For example, `.example.com` will allow `example.com`, `foo.example.com`, and `foo.bar.example.com`.
   *
   * If set to `true`, the server is allowed to respond to requests for any hosts.
   * This is not recommended as it will be vulnerable to DNS rebinding attacks.
   */
  allowedHosts?: string[] | true;
}

What was changed

• Corrected the type of preview.allowedHosts from string | true to string[] | true.
• Kept the rest of the description and default value as is, linking to server.allowedHosts for details.

Why this change is necessary

• Provides accurate and consistent documentation.
• Helps users understand the correct expected configuration type for preview.allowedHosts.

[sapphi-red]

Thanks!