documentation

Pull request #762: feature/ZBX-20298-6.4-D-API (updated Action API examples).

Merge in WEB/documentation from feature/ZBX-20298-6.4-D-API to release/6.4

* commit 'ffba2c5b343ed733932233ff1e1a7d630da835ba':
  [ZBX-20298] Removed params "pause_suppressed", "notify_if_canceled"
  [ZBX-20298] Updated action.create examples
  [ZBX-20298] Updated "action.create" page: `esc_period` value & example description
  [ZBX-20298] Updated examples in action.create & .update