documentation

Pull request #3471: feature/ZBXNEXT-9424-7.5-D

Merge in WEB/documentation from feature/ZBXNEXT-9424-7.5-D to release/8.0

* commit '1650d3f964fbc09c1eb112108f08480810f837fe':
  [ZBXNEXT-9424] clarified "Color interpolation" parameter behavior
  [ZBXNEXT-9424] fixed shortcomings
  [ZBXNEXT-9424] fixed shortcomings
  [ZBXNEXT-9424] added changelog entry for templatedashboard API; added section on downloading Scatter plot PNG
  [ZBXNEXT-9424] removed blockID
  [ZBXNEXT-9424] fixed blockID
  [ZBXNEXT-9424] added missing "Color palette" parameter from ZBXNEXT-8919
  removed redundant description of "Show legend" parameter behavior
  [ZBXNEXT-9424] fixed shortcomings from ZBXNEXT-10141
  [ZBXNEXT-9424] added new widget: Scatter plot (API)
  [ZBXNEXT-9424] copy-pasted Graph widget page as template for Scatter plot widget page; updated widget page numbering (API)
  [ZBXNEXT-9424] added new widget: Scatter plot
  [ZBXNEXT-9424] copy-pasted Graph widget page as template for Scatter plot widget page; updated widget page numbering