documentation

[ZBXNEXT-6974] added new parameters "trigger_severities" and "groupBy" in event.get; added new widget module type "toptriggers"

* commit 'e3dd5b02a9c2d5a3d7b99715cd6dd9ae3ca35730':
  [ZBXNEXT-6974] fixed wording
  [ZBXNEXT-6974] fixed wording
  [ZBXNEXT-6974] listed deprecated parameters; changed sub-headings to h5
  [ZBXNEXT-6974] fixed wording
  [ZBXNEXT-6974] fixed widget field order
  [ZBXNEXT-6974] added new widget module type toptriggers
  [ZBXNEXT-6974] added new parameter "trigger_severities"; deprecated parameters "select_acknowledges" and "select_alerts"; updated examples