Table on viewer source is missing the header

AFFECTS:

• Main/?viewer=code

ERROR:

• ERROR: At least one table has been found that uses no th element.
• ERROR: No headers or id attributes have been found. When not using these be advised to use the scope attribute instead to associate table labels (<th> cells) with columns and rows. (see R-pd.11.4).

INVALIDATES:

• Dutch Guidelines: {{validateRpd11s2() }}
  • https://github.com/xwiki/xwiki-platform/blob/master/xwiki-platform-tools/xwiki-platform-tool-standards-validator/src/main/java/org/xwiki/validator/DutchWebGuidelinesValidator.java#L1065
• R-pd.11.2 "Use the th (table header) to describe a column or row in a table with relational information."

EXPLANATION:

• Data tables should contain a header
  Tables which contain data (as opposed to layout tables) should contain proper table header elements to mark them for screen readers and enhance the structure of the document.

FIXES:

• VAR1: Add a th for the table