delete all $~json.cache[n] variables, up to $json.config.cache.maxdepth.

[dansmith65]

There is a temporary method in place for this, and a comment in the code, along with an idea for an alternative method.

https://github.com/dansmith65/FileMaker-JSON-Functions/blob/26ab18216e13a357c428697ae89d360906a6926f/Functions/z_jsonParseSupport1.fmfn#L689