documentation

Pull request #4443: Feature/ZBXNEXT-7704 7.5 D

Merge in WEB/documentation from feature/ZBXNEXT-7704-7.5-D to release/8.0

* commit 'cab2b4a2a704c1423d0870f1dc0f9257aad29397':
  [ZBXNEXT-7704] added note about agents
  [ZBXNEXT-7704] fixed comments
  [ZBXNEXT-7704] updated pattern examples
  [ZBXNEXT-7704] added What's new entry
  [ZBXNEXT-7704] updated description of Restricting agent checks
  [ZBXNEXT-7704] added AllowKeyRegexp and DenyKeyRegexp agent config parameters
  [ZBXNEXT-7704] updated formatting
  [ZBXNEXT-7704] added AllowKeyRegexp and DenyKeyRegexp agent config parameters
  [ZBXNEXT-7704] added AllowKeyRegexp and DenyKeyRegexp agent config parameters