fix: use the correct filetype for javascriptreact

[imobachgs]

First of all, thanks for such a handy plugin :-)

This PR fixes a problem I found while working with a javascriptreact file. It is just a typo (a missing 's') that causes the runner to not be assigned to that kind of files.

As a workaround, you can just set the proper value in your call to the setup function:

test.setup {
  -- other options...
  runners = {
    javascriptreact = "nvim-test.runners.jest"
  }
}

I hope it helps.

Thanks!