New template: Pediatrics

Just as a heads up for anyone interested, I am starting a template for submission to the journal Pediatrics.

This is my first time submitting to rticles, so I might like some feedback as I get further along the process, so if anyone is particularly savvy in medical journal submissions and interested in helping, please reach out.

By filing an issue to this repo, I promise that

• I have fully read the issue guide at https://yihui.name/issue/.
• I have provided the necessary information about my issue.
  • If I'm asking a question, I have already asked it on Stack Overflow or RStudio Community, waited for at least 24 hours, and included a link to my question there.
  • If I'm filing a bug report, I have included a minimal, self-contained, and reproducible example, and have also included xfun::session_info('rticles'). I have upgraded all my packages to their latest versions (e.g., R, RStudio, and R packages), and also tried the development version: remotes::install_github('rstudio/rticles').
  • If I have posted the same issue elsewhere, I have also mentioned it in this issue.
• I have learned the Github Markdown syntax, and formatted my issue correctly.

I understand that my issue may be closed if I don't fulfill my promises.

No file, test, or entry point is named. Start by reviewing the existing rticles journal templates and the Pediatrics journal requirements linked in the issue. Done means a complete template that matches the journal's submission format and fits the repository's existing template structure.