5567: SSR: Wrap placeholder expansions in parenthesis when necessary r=matklad a=davidlattimore
e.g. `foo($a) ==> $a.to_string()` should produce `(1 + 2).to_string()` not `1 + 2.to_string()`
We don't yet try to determine if the whole replacement needs to be wrapped in parenthesis. That's harder and I think perhaps less often an issue.
Co-authored-by: David Lattimore <dml@google.com>
9042009b7f