Add support for recursive types in JsonSchema

[shashitnak]

Problem
Current implementation of JsonSchema doesn't support recursive types.

pub enum JsonSchema {
    Obj(HashMap<String, JsonSchema>),
    Arr(Box<JsonSchema>),
    Opt(Box<JsonSchema>),
    Enum(BTreeSet<BTreeSet<String>>),
    Str,
    Num,
    Bool,
}

The type definition has to be updated to support recursive types.

[github-actions]

Action required: Issue inactive for 30 days.
Status update or closure in 7 days.

[github-actions]

Issue closed after 7 days of inactivity.