feature: improve dump operator documentation

[jorgeaguileraseqera]

closes #3159

Signed-off-by: Jorge Aguilera [email protected]

[Midnighter]

I think a better approach would be to use a JsonGenerator with appropriate converters which for paths could look like:

import static groovy.json.JsonOutput.prettyPrint
import groovy.json.JsonGenerator
import java.nio.file.Path

JsonGenerator generator = new JsonGenerator.Options()
        .addConverter(Path) { Path filename -> filename.toString() }
        .build()

prettyPrint(generator.toJson(it))

[pditommaso]

Merge manually via 4218b299