Add YARD docs to Faker::JSON (#2000)

* Add YARD docs to Faker::JSON

* fix non-continuing comment line error

lib/faker/default/json.rb

@@ -3,6 +3,23 @@ class Json < Base
     require 'json'
 
     class << self
+      ##
+      # Produces a random simple JSON formatted string.
+      #
+      # @param width [Integer] Specifies the number of key-value pairs.
+      # @param options [Hash] Specifies a Faker gem class to use for keys and for values, respectably. options_hash = {key: Class.method, value: Class.method}
+      # @return [Hash{String => String}]
+      #
+      # @example
+      #   Faker::Json.shallow_json(width: 3, options: { key: 'RockBand.name', value: 'Seinfeld.quote' }) # =>
+      #     {"Parliament Funkadelic":"They're real, and they're spectacular.",
+      #     "Fleetwood Mac":"I'm not a lesbian. I hate men, but I'm not a lesbian.",
+      #     "The Roots":"It became very clear to me sitting out there today that every decision
+      #     I've made in my entire life has been wrong. My life is the complete opposite of everything
+      #     I want it to be. Every instinct I have, in every aspect of life, be it something to wear,
+      #     something to eat - it's all been wrong."}
+      #
+      # @faker.version 1.9.2
       def shallow_json(legacy_width = NOT_GIVEN, legacy_options = NOT_GIVEN, width: 3, options: { key: 'Name.first_name', value: 'Name.first_name' })
         warn_for_deprecated_arguments do |keywords|
           keywords << :width if legacy_width != NOT_GIVEN
@@ -16,6 +33,44 @@ def shallow_json(legacy_width = NOT_GIVEN, legacy_options = NOT_GIVEN, width: 3,
         JSON.generate(hash)
       end
 
+      ##
+      # Produces a random nested JSON formatted string that can take JSON as an additional argument.
+      #
+      # @param json [Hash{String => String}] Specifies a Json.shallow_json and uses its keys as keys of the nested JSON.
+      # @param width [Integer] Specifies the number of nested key-value pairs.
+      # @param options [Hash] Specifies a Faker gem class to use for nested keys and for values, respectably. options_hash = {key: Class.method, value: Class.method}
+      # @return [Hash{String => String}]
+      #
+      # @example
+      #   json = Faker::Json.shallow_json(width: 3, options: { key: 'Name.first_name', value: 'Name.last_name' })
+      #   puts json # =>
+      #     {"Alisha":"Olson","Everardo":"DuBuque","Bridgette":"Turner"}
+      #
+      #   json2 = Faker::Json.add_depth_to_json(json: json, width: 2, options: { key: 'Name.first_name', value: 'Name.last_name' })
+      #   puts json2 # =>
+      #     {"Alisha":{"Daisy":"Trantow","Oda":"Haag"},
+      #      "Everardo":{"Javier":"Marvin","Eliseo":"Schuppe"},
+      #      "Bridgette":{"Jorge":"Kertzmann","Lelah":"MacGyver"}}
+      #
+      #    json3 = Faker::Json.add_depth_to_json(json: json2, width: 4, options: { key: 'Name.first_name', value: 'Name.last_name' })
+      #      puts json3 # =>
+      #        {"Alisha":
+      #          {"Daisy":
+      #            {"Bulah":"Wunsch","Cristian":"Champlin","Lester":"Bartoletti","Greg":"Jacobson"},
+      #           "Oda":
+      #             {"Salvatore":"Kuhlman","Aubree":"Okuneva","Larry":"Schmitt","Velva":"Gibson"}},
+      #         "Everardo":
+      #           {"Javier":
+      #             {"Eduardo":"Orn","Laila":"Kub","Thad":"Legros","Dion":"Wilderman"},
+      #           "Eliseo":
+      #             {"Olin":"Hilpert","Marisa":"Greenfelder","Karlee":"Schmitt","Judd":"Larkin"}},
+      #         "Bridgette":
+      #           {"Jorge":
+      #             {"Eloy":"Pfeffer","Kody":"Hansen","Paxton":"Lubowitz","Abe":"Lesch"},
+      #           "Lelah":
+      #             {"Rick":"Wiza","Bonita":"Bayer","Gardner":"Auer","Felicity":"Abbott"}}}
+      #
+      # @faker.version 1.9.2
       # rubocop:disable Metrics/ParameterLists
       def add_depth_to_json(legacy_json = NOT_GIVEN, legacy_width = NOT_GIVEN, legacy_options = NOT_GIVEN, json: shallow_json, width: 3, options: { key: 'Name.first_name', value: 'Name.first_name' })
         # rubocop:enable Metrics/ParameterLists