Updated SAS weighted logrank test page - #625

Hi @dimpz4295, thanks so much for contributing these two PRs! Before we review the content, please could you pull down from the main CAMIS branch into your forked branch and add library(tibble) to your package calls for both PRs?

Hi @abiterry yes I can! I apologize for that. I'll do that as soon as I can and fix the errors.

Hi @abiterry! I've pulled the latest changes from the main CAMIS branch into my ancova-fix branch and 'weighted log rank SAS page' branch, added library(tibble) to the package calls, and pushed the updates to my fork. Thank you.

Hi @dimpz4295 - just saw you pushed ANCOVA in a separate PR that now runs clean. Can you just remove ANCOVA change from this PR, then we can bring them both in separately. Thanks !

Thanks @dimpz4295 - This has been pulled in through a new PR #627 because I think if I pull in this PR, ANCOVA will be changed back to the original (before your PR#626)! You should be able to see the changes live on the repo by latest tomorrow. Do let @abiterry and me know if any issues.