add ":not" to negate css prop selector

[arch-mage]

this change based on this issue.

P.S: I've never done any pull request to any project before. This is my first time, please tell me if I did something wrong or I miss anything important.

[aweary]

@arch-mage great work on your first PR, we really appreciate it! This is going to be affected by #458, which totally reimplements how we parse selectors, so I'm not sure if we want to merge this if it's not going to be compatible.

[ljharb]

Personally I like the idea of merging this first, and then making sure #458 still passes the new tests after a rebase :-)

[aweary]

That's fine with me :) @arch-mage can we add some more tests to verify that this works with other selectors like classes and ids?

':not(.foo)'
':not(#bar)'

I think ideally we'd have a negation test for every query combination/type we support. We've had a number of issues arise from corner cases with our regex parsers.

[arch-mage]

I think it's better to wait for #458 first. Because, when I wrote this, i only think about negating attribute. So it won't work on :not(#foo) or :not(.bar). It's kind a little hacking I think, which obviously will break. I will see then, if I can do adding :not selector

[ljharb]

@aweary is this still needed in v3?

[aweary]

@ljharb it's still needed, but this PR is now totally outdated. I'll be sending a PR for this today 😃 @arch-mage thanks for your work on this, sorry we didn't get it merged!