public method to decode/unquote raw json string literals

Created by: proppy

Is there a reason the methods for "parsing" (or unquote) json strings literals are private? https://github.com/bblanchon/ArduinoJson/blob/master/src/Internals/JsonParser.cpp#L146

In addition to documented methods for parsing objects and arrays on the main JsonBuffer class, other literals (bool, int, float) can be simply converted thru Arduino::JsonVariant or ArduinoJson::Internals::parse, but it doesn't seems to be possible to unquote raw json string literals with the current public API.

(suggested tag: question)