documentation

Pull request #1949: feature/ZBXNEXT-9297-7.2-D. Dynamic unit size in Clock widget.

Merge in WEB/documentation from feature/ZBXNEXT-9297-7.2-D to release/7.2

* commit 'c40f631cba664b2f5472e6c06760c552273bde50':
  [ZBXNEXT-9297] updated dashboard.png
  [ZBXNEXT-9297] updated dashboard.png
  [ZBXNEXT-9297] Dynamic unit size in Clock widget