Support for anything-but - suffix - equals-ignore-case

I was hoping to see that I could check a suffix with equals-ignore-case however that doesn't seem to be the case.

I see that anything-but on a suffix is supported
```
{
"detail": {
"instance-id": [ { "anything-but": { "suffix": "1234" } } ]
}
}
```

However equals-ignore-case is not
```
"FileName": [
{
"anything-but": { "suffix": { "equals-ignore-case": ".png" }
}
]
}

``

Were there any plans to support this ?

Thanks

Start by locating the suffix matching path and the existing handling for `anything-but` and `equals-ignore-case`. Use the two JSON examples as the behavioral reference; done means the nested `anything-but` suffix expression supports case-insensitive matching.

Written by the indexing model from the issue text.