Use quotes to improve error messages

[kud1ing]

Since Haskell's [1 .. 10] is not (yet) implemented in Rust and i read about ranges, i tried

let a = [1 to 10];

this gives the baffling error message

error: expecting ,, found to

A more readable version would be

error: expecting "," but found "to"

[kud1ing]

All uses of p.fatal() in src/comp/syntax/parse/parser.rs should be checked

Single-quotes are in use already: "expecting '::' or ';'"

[kud1ing]

You are fast, thank you.
Took me the chance to try doing this myself. ;(