documentation

Pull request #3334: Feature/ZBXNEXT-7744 7.0 D

Merge in WEB/documentation from feature/ZBXNEXT-7744-7.0-D to release/7.0

* commit '9f0552e1922958bbf1f4fc58094d81536828838b':
  ZBXNEXT-7744 fixed a what's new entry and a comment.
  ZBXNEXT-7744 added a what's new entry.
  ZBXNEXT-7744 added new parameters and comments cell content for Redis.
  ZBXNEXT-7744 formatting.