title: Adding significant result as superscripts, new column for other stat, and transpose the group in tbl_summary
body: <p>I love <code>gtsummary</code> package. After a while playing with it, I have finished my almost-ideal-table of mine. However, are there anyway I can add significant superscripts to values in tbl_summary (both manually or automatically)? Also, is it possible to add a new stat column to show something like PSE (I can calculate it manually, but having a hard time to combine it into the summary table. Last but not least, is it possible to transpose the grouping from the <code>by</code> argument to the rows instead of column?</p>
  <p>Thank you.</p>
  <p><a href="https://i.stack.imgur.com/BCEsj.png" rel="nofollow noreferrer">Desired Table</a></p>