documentation

Pull request #2700: Feature/ZBX-26060 7.0 D

Merge in WEB/documentation from feature/ZBX-26060-7.0-D to release/7.0

* commit '8b907c2b49486572bc8ad2c062a91faace1bb67d':
  ZBX-26060 fixed a comment block.
  ZBX-26060 fixed a task link, added a link for the MySQL bug.
  ZBX-26060 deleted the mention of the Zabbix version.
  ZBX-26060 added an entry about group replication.