documentation

Pull request #1609: feature/ZBX-23758-7.0-D2. Refined export element tables.

Merge in WEB/documentation from feature/ZBX-23758-7.0-D2 to release/7.0

* commit '014c6ecf533cc98657b24157e444243971793730':
  [ZBX-23758] Better row/column merge
  [ZBX-23758] Better row/column merge
  [ZBX-23758] Enlarged "Footnotes" heading
  [ZBX-23758] Added missing footnote
  [ZBX-23758] Possible values made consistent; removed redundant note
  [ZBX-23758] Added missing elements, reordered elements
  [ZBX-23758] Updated heading size
  [ZBX-23758] Added line breaks; refined some wording
  [ZBX-23758] Fixed broken formatting and refined footnote wording
  [ZBX-23758] Fixed footnote format
  [ZBX-23758] Fixed block ID
  [ZBX-23758] Refined export element tables