False positive for unreachable_code_linter() on inline expressions

```r
lint("function(x) if (x > 2) stop() else x\n", unreachable_code_linter())
# <text>:1:31: warning: [unreachable_code_linter] Code and comments coming after a return() or stop() should be removed.
# function(x) if (x > 2) stop() else x
#                               ^~~~
```

This may be a regression; cc @MEO265.