documentation

Pull request #1927: feature/ZBX-24978-7.2-D. Restored removed info on "zabbix[proxy,<name>,<param>]" item, clarified "Item key details", and refined page style and punctuation.

Merge in WEB/documentation from feature/ZBX-24978-7.2-D to release/7.2

* commit '863f5a2987ba74e37675851cdf24cf2ec0cebcc5':
  [ZBX-24978] added param-seperating commas
  [ZBX-24978] refined page style
  [ZBX-24978] refined page style and punctuation
  [ZBX-24978] adjusted item key list to be consistent
  [ZBX-24978] adjusted item key list to match described behavior
  [ZBX-24978] clarified behavior of internal check item keys
  [ZBX-24978] clarified "Item key details"
  [ZBX-24978] restored and refined removed "fuzzytime" function info on "zabbix[proxy,<name>,<param>]" item
  [ZBX-24978] refined "zabbix[proxy,<name>,<param>]" item "param" parameter possible values description
  [ZBX-24978] added short "zabbix[proxy,"Germany",lastaccess]" example description
  [ZBX-24978] restored removed info on "zabbix[proxy,<name>,<param>]" item