Some char literals trigger parsing error

Observe

``` bash
# mirah -e 'puts(?A )'
A
# mirah -e 'puts(?A)'
A
# mirah -e 'puts(?\u0041 )'
A
# mirah -e 'puts(?\u0041)'
DashE:1:

ERROR: expected tRParen before '?\u0041)'
puts(?\u0041)
     ^
DashE failed to parse.
1 errors
```

It is expected that

``` mirah
puts(?\u0041)
```

parses correctly.
