Requesting parse function that takes in Data instead of String

[bjo0]

It would be convenient to have a version of the parse func that took in Data instead of String, as the conversion of Data to String involves transiting an Optional<String> function (String(data: encoding:)). This maybe looks superficially like not an inconvenience, but in practice it means I have to make my own error type in order to propagate failures at this step. If SwiftSoup did it and implemented the error type, it would improve ergonomics.

The function signature might be something like this:

func parse(data: Data) throws -> Document

[aehlke]

I will merge a PR for this if you want to implement it