Feature request: value_foo equivalent for column headers

[danielroseman]

I recently used the export functionality with a table, and it worked perfectly except for one issue. Our column headers are highly customised, via defining verbose_name, to add popup explanations in HTML. Clearly that HTML is irrelevant in the export - but the only way I could see to remove it was to define an identical column without the custom header, mark it as invisible, and exclude the original column from the export.

It would be great if there was some equivalent of the values_foo method to make it possible to output the header without any customisation. Or possibly even a plain_verbose_name attribute that defaults to the value of verbose_name.

What do you think? Happy to contribute a PR if you think this would be useful.