Restore row striping option in stub cells (row.striping.include_stub = TRUE)

[rich-iannone]

This simply moves the .gt_striped rule below others to increase precedence.

Thanks @gergness for creating the PR that prompted this one (#537). We ultimately decided to go with this change (which restores the earlier behavior) since it work better with HTML style inlining (using as_raw_html()).

Testable code from @gergness, where the yellow row stripes are also present in the stub cells (leftmost column).

library(gt)

exibble %>% 
  gt(rowname_col = "row") %>% 
  opt_row_striping() %>% 
  tab_options(
    row.striping.include_stub = TRUE,
    row.striping.background_color = "yellow"
  )

Fixes: #536

[markbneal]

If you need this working in a hurry (like I do), and its not yet in the released version, replace the gt_styles_default.scss file on your computer with the one on the branch that fixes this, from: https://github.com/rstudio/gt/blob/restore-row-striping-stub/inst/css/gt_styles_default.scss

Another handy hint - if you are using gt row striping in a gitbook format (e.g. with bookdown) and the row striping is going a bit strange (e.g. grey where you weren't expecting it), you may need to change the default 'plugin-table.css' on your computer, and change the striping colour there to something that won't cause a problem - e.g. I changed table tr:nth-child(2n){background-color:#f8f8f8} to table tr:nth-child(2n){background-color:#fff}, which meant it is now white instead of grey. Note that the way gt counts every second row is different to how the bookdown default css counts every second row when you have row grouping.