Missing Unicode Greek Characters in Bookdown LaTeX
I spent this morning fighting with Bookdown. I was going through reviewer notes for the R Cookbook 2nd Edition and my coauthor, Paul Teetor, had noted that some of the greek symbols we were using were not showing up in the text when the book was rendered to PDF. Oddly, it looked fine in HTML. This turned out to be a font issue. I was using XeLeTeX as my \(\LaTeX\) engine specifically because it handles UTF-8 unicode well.