Fix error reporting for one_or_more rule

[obenjiro]

Right now if we parse wrong PEG grammar we got this

Unexpected "s" expected (EOF)
1: GRAMMAR test a -> "A"; should_fail -> "B" -
--------------------------^

We should get more informative error message, like this

Unexpected "-" expected (;)
1: GRAMMAR test a -> "A"; should_fail -> "B" -
---------------------------------------------^ 

[obenjiro]

fixed in 26bf50b