fix(templates): correct hash handling for redirects in redirect.html

[zoobestik]

The main change is an improvement to how the script appends the current hash to the redirect URL, ensuring that any pre-existing hash in the target URL is properly replaced.

Wrong case:

/docs/js-hands-ons.html#test => /docs/js-overview.html#get-started-with-kotlin-js#test

Examples:

1. Without hash in config

   - from: /docs/file.html
      to: github.com/...

    - /docs/file.html => github.com/...
    - /docs/file.html#anchor => github.com/...#anchor

2. With hash in config

   - from: /docs/file.html
      to: github.com/...#new-anchor

    - /docs/file.html => `github.com/...#new-anchor`
    - /docs/file.html#anchor => github.com/...#anchor

Redirect logic improvements:

• Updated the JavaScript redirect code to check for and remove any existing hash fragment from the url before appending the current window location hash. This ensures that only one hash is present in the final URL and prevents malformed redirects.
• Replaced the previous inline script with a more robust and minified version, and wrapped the unminified version in a template comment for clarity and maintainability.