Add blocklist to prevent tailwind from generating incorrect css

[paoloredis]

Tailwind is currently generating css from this comment on this page:

# Format: redis+sentinel://[username:password@]host1:port1,host2:port2/service_name[/db]

into

.\[username\:password\@\] {
  username: password@;
}

The comment doesn't exist for versions earlier than 0.9.0, which is why the css generated for those versions has a different hash.

The fix is to prevent tailwind from generating unwanted css.

[github-actions]

DOC-5835

[andy-stark-redis]

Well done! Definitely approved :-)