Add yard docs for Faker::Coffee methods (faker-ruby#1810)

* Add yard docs for Faker::Coffee methods

* @faker.version should be 1.9.0

lib/faker/default/coffee.rb

@@ -5,24 +5,69 @@ class Coffee < Base
     flexible :coffee
 
     class << self
+      ##
+      # Produces a random blend name.
+      #
+      # @return [String]
+      #
+      # @example
+      #   Faker::Coffee.blend_name #=> "Major Java"
+      #
+      # @faker.version 1.9.0
       def blend_name
         parse('coffee.blend_name')
       end
 
+      ##
+      # Produces a random coffee origin place.
+      #
+      # @return [String]
+      #
+      # @example
+      #   Faker::Coffee.origin #=> "Oaxaca, Mexico"
+      #
+      # @faker.version 1.9.0
       def origin
         country = fetch('coffee.country')
         region = fetch("coffee.regions.#{search_format(country)}")
         "#{region}, #{country}"
       end
 
+      ##
+      # Produces a random coffee variety.
+      #
+      # @return [String]
+      #
+      # @example
+      #   Faker::Coffee.variety #=> "Red Bourbon"
+      #
+      # @faker.version 1.9.0
       def variety
         fetch('coffee.variety')
       end
 
+      ##
+      # Produces a string containing a random description of a coffee's taste.
+      #
+      # @return [String]
+      #
+      # @example
+      #   Faker::Coffee.notes #=> "dull, tea-like, cantaloupe, soy sauce, marshmallow"
+      #
+      # @faker.version 1.9.0
       def notes
         parse('coffee.notes')
       end
 
+      ##
+      # Produces a random coffee taste intensity.
+      #
+      # @return [String]
+      #
+      # @example
+      #   Faker::Coffee.intensifier #=> "mild"
+      #
+      # @faker.version 1.9.0
       def intensifier
         fetch('coffee.intensifier')
       end