code: private Content getValue(FieldDoc member) {
          Content valueContent = new StringContent(member.constantValueExpression());
          Content code = HtmlTree.CODE(valueContent);
          return HtmlTree.TD(HtmlStyle.colLast, code);
      }
docs: Get the value column for the constant summary table row.
  
  @param member the field to be documented.
  @return the value column of the constant table row