Non-idempotence with comment in tuple or paren

Input:
```
x = ({-a-}b, c)
```

Error:
```
Formatting is not idempotent:
  before: "x = (\n  {-a-} b)\n"
  after:  "x =\n  ( {-a-} b\n  )\n"
```

This also happens with a simple parenthesis:
```
x = ({-a-}b)
```
Results in:
```
Formatting is not idempotent:
  before: "x = (\n  {-a-} b)\n"
  after:  "x =\n  ( {-a-} b\n  )\n"
```