Unnecessary display statement

[mattgarrish]

In the detailed conformance section, the certification date output has "on" as its own display statement:

IF certification_date: THEN display "The publication was certified ".
display " on "
display certification_date.

I believe this is an artefact from when the certifier name was duplicated here, but it should be possible to add "on" back to the first display statement now.

[mattgarrish]

This check also seems differently formatted from others like it. A few bullets above, for example, a bullet list separates the display statements from the "THEN". Following that pattern, this should be:

IF certification_date: THEN

• display "The publication was certified on "
• display certification_date.