feat: add wildcard * class to ignore classes when matching parent elements

[hmnd]

Fixes #308 by introducing a wildcard class selector for html paths. When a wildcard is used, a new element option ignoreClass is enabled which bypasses checking attribute equality in Element.prototype.matchesElement.
I'm new to lop, so I know the rule I've setup has a hole which would count * as a regular class if * is used in conjunction with another class. Would appreciate some guidance on how I would go about preventing that.

Thanks for this awesome project!

[hmnd]

For others looking for a solution to this before it gets merged (hopefully), I've published the PR as @icewolf/mammoth@1.4.20-bleeding.0.

[mwilliamson]

Hmm, I'm not sure about the syntax. Ideally we'd do something similar to CSS, although I'm not sure there's any syntax that would actually cover this (since the existing matchers require an exact match, whereas CSS selectors allow extra attributes/classes).

An alternative might be something like p:ignore-class or p:ignore(class) (where the latter in principle allows other attributes to be ignored, not that you can set other attributes at the moment).

[mwilliamson]

Closing due to inactivity. If anybody wants to keep discussing it, please do so on #308.