@Kha the pretty printer fails when we use the `fun+match` macro. Example:
```
fun
| PSum.inl a => 1 + sizeof a
| PSum.inr b => 1 + sizeof b
```
The test `Reparen.lean` fails without this commit. Here is the error message
```
error: no known parenthesizer for kind 'Lean.Parser.Term.matchAlts'
```
8c6f536367