Steps to replicate the issue (include links if applicable):

• Copy the Capiunto example usage
• Before the return statement include :addWikitext("some test wikitext")
• Try to add a rowClass (you cannot because the argument is not exposed)

What happens?: Wikitext is created with no row class name or similar

What should have happened instead?: I should have been able to add class names to the wikitext row.

Why should this have happened?: For recreating infoboxes like [[ en.wikipedia.org/wiki/Template:Infobox_country | Template:Infobox country ]], we have to include the mergedrow class, which we currently cannot do

Software version (skip for WMF-hosted wikis like Wikipedia): 1.41

Other information (browser name/version, screenshots, etc.):

↑Screenshot of current behavior—take note of the last row which is using a Capiunto-ported version of [[ en.wikipedia.org/wiki/Template:Infobox_country/multirow | Template:Infobox country/multirow ]]. The top border should not be there because the added <tr> does not allow me to set the mergedrow class

↑Screenshot after using inspect element to achieve desired results—I have added the mergedrow class to the first <tr> as expected.

How can you/others fix this?: By exposing at least the rowClass attribute similar to :addRow in the :addWikitext method