any way to automatically add braces for single line statement?

Any way to automatically add braces for single line code inside `if` or something like that?

For the source code like this:

``` r
if (TRUE)
  a = 1
b = 2
```

Current default result for `tidy_source()`:

``` r
if (TRUE) a = 1
b = 2
```

Expected formatted result (of the requested feature):

``` r
if (TRUE) {
  a = 1
}
b = 2
```
