Feature Request: Add Varga & Delaney's A

[sammerk]

Great approach and my students especially love the jamovi plugin! Just want to suggest to add the effect size A for ordinal variables. It is straight forward and usually students get it in a few minutes.

Vargha, A., & Delaney, H. D. (2000). A critique and improvement of the CL common language effect size statistics of McGraw and Wong. Journal of Educational and Behavioral Statistics, 25(2), 101–132. https://doi.org/10.3102/10769986025002101