Wax should allow unescaped ',' and ':' outside Alternatives and Repetitions

[brunoschmidt]

Wax restricts the use of literals containing ',' and ':' because of their use on Alternatives and Repetitions and the fact that they recurse on glob, but it restricts literals unnecessarily with such characters.

I believe that literal should be parametrized with the restriction on those characters only when they are in use by the expression, making escaping optional when they are not in use.

Today a literal like this will break without scaping:

Glob::new("extra:dots.txt").unwrap();

Causing the following error:

panicked at 'called `Result::unwrap()` on an `Err` value: BuildError { kind: Parse(ParseError { expression: "extra:dots.txt", locations: [ErrorEntry { fragment: ":dots.txt", location: 5, kind: Nom(Eof) }] }) }'