Generalize inline ignore rules

[woodruffw]

This follows #187, which addresses #124:

I think we want a bit more syntax here to enable multiple ignores.

For example:

1. Ignore everything: # zizmor: ignore[*]
2. Ignore two or more rules: # zizmor: ignore[rulea,ruleb]

As part of this generalization, we should also probably switch to using yamlpath's comment extraction APIs.

Originally posted by @woodruffw in #187 (comment)

[woodruffw]

woodruffw/yamlpath#3 will add Document::feature_comments, which in turn will make it possible to extract multiple comments per yamlpath feature.

Edit: I believe the trick here will be moving the # zizmor: ignore logic from FindingBuilder::build into SymbolicLocation::concretize, which will then produce a Location struct with a new ignored attribute.

From there, Finding::ignored should become any(loc.ignored for loc in locations).

[woodruffw]

I thought about it a bit, and I'm going to hold off on ignore[*] for now -- that's going to be too much of a footgun.