VS Code Format selection does not work when selection ends with non-code

## Buggy behavior

Consider this block of R code

```{r}
mtcars |> 
names()
# blank line
names(mtcars)
```

Selecting lines 1-3 and "Format Section" in VS Code does not do anything. 

## Expected behavior

Selectin lines 1-2 or 1-4  and "Format Section" in VS Code formats the code correctly:

```
mtcars |>
    names()
```
