Do not use custom output prefix

As this breaks pkgdown styling: ropensci-org/rotemplate#56

Author: jeroen

vignettes/intro.Rmd

@@ -16,7 +16,7 @@ vignette: >
 
 ```{r, echo = FALSE, message = FALSE}
 library(tibble)
-knitr::opts_chunk$set(comment = "")
+#knitr::opts_chunk$set(comment = "")
 has_nld <- "nld" %in% tesseract::tesseract_info()$available
 ```