A tabular is not a block

[rbeezer]

The tabular element is considered a block by the template with mode="is-block", which has caused an idx inside a tabular to not know how to make an index entry (number, name).

• Perhaps this should be mode="is-addressable-target" or similar.
• In any event, could be as simple as removing tabular from the list.
• Rework the template? Put all instances in a global variable and check membership?
• Review the (limited) uses of current template.