Consider exporting common errors thrown by this crate

[jannisbecker]

Some returned Results returned by scraper functions use error types from the cssparser crate.
Unfortunately in my project, I cannot handle them (e.g. using thiserror) without adding cssparser to my dependencies as well, even though I don't need it anywhere else.

Please consider reexporting cssparser, or alternatively define error types for the scraper crate and export those.

Let's define a common error struct for scraper so that crates using it can integrate it in their error handling.

[mainrs]

The better approach would probably be to define error types in scraper itself and export those.

[jannisbecker]

Sounds good, yeah. It solves the same issue, so feel free to see this as the solution of this ticket.

[cfvescovo]

This is now being addressed in PR #95.
Thanks to @kiwifruit