documentation

Pull request #2112: DEV-3947 changed the comment for the last(/host/key) function using proper syntax (sub-issue 19)

Merge in WEB/documentation from feature/DEV-3947-7.2-D19 to release/7.2

* commit 'e1dba9750334ac4ed859724b1a635e8d989ef43b':
  DEV-3947 missing dot added (sub-issue 19).
  DEV-3947 nodata() is now a hyperlink
  DEV-3947 "date and time" and nodata() functions" changed to "date and time" and/or nodata() functions", link to the calculation time is provided (sub-issue 19.1)
  DEV-3947 term "time-based functions" changed to "date and time" and nodata() functions" (sub-issue 19.1)
  DEV-3947 further clarification to inform that nodata cannot be used with date and time functions wo other functions referencing the host item (sub-issue 19.1)
  DEV-3947 clarification to avoid confusion between date and time function and time-based functions (sub-issue 19.1)
  DEV-3947 changed the comment for the last(/host/key) function using proper syntax (sub-issue 19)