fix: correctly parse nested element selectors

[SwetaTanwar]

Prerequisites checklist

• I have read the contributing guidelines.

What is the purpose of this pull request?

What changes did you make? (Give an overview)

Related Issues

Fix #84

Is there anything you'd like reviewers to focus on?

added tests in css repo as well - eslint/css#349

[coveralls]

Pull Request Test Coverage Report for Build 21257866981

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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Details

• 41 of 41 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.006%) to 98.557%

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Totals
Change from base Build 20089849670:	0.006%
Covered Lines:	11968
Relevant Lines:	12109

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💛 - Coveralls

[snitin315]

LGTM, leaving it open for 2nd review

[nzakas]

Thanks for looking at this. Can you add a test with a comma in the selector?

main {
  p:first-of-type, span {
    margin-top: 0;
  }
}

[SwetaTanwar]

@nzakas Done.