Fix canonicalization of arbitrary variants with attribute selectors

[thecrypticace]

Fixes tailwindlabs/tailwindcss-intellisense#1481

We were detecting when we needed to apply the * and ** variants and even detecting attribute selectors. However we only cleaned up the attribute selectors when they were data-* or aria-* attributes. This resulted in a "loop" of sorts because we'd:

• See something like [&_>_[foo]]:flex
• Notice that it needs a * variant
• Add the * variant, giving *:[&_>[foo]]:flex
• But fail to cleanup the remainder of the variant

This then meant that we'd see the *:[&_>[foo]]:flex the next time we checked, notice that it still needed a * variant, and repeat…

This PR fixes this case to clean up the selector.