I'd like to have line numbers for code blocks in my R Markdown documents. When I follow Yihui Xie's cookbook, I think I should end up with this code:
---
title: "Untitled"
author: "Unauthored"
date: "0/20/2020"
output:
html_document:
highlight: tango
---
```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```
## Line numbers
```{r, attr.source='.numberLines'}
if (TRUE) {
x <- 1:10
x + 1
}
```
But it gives me no line numbers:
Is it me?