[ruby/json] Update method docs for JSON.load and JSON.unsafe_load to show the correct use of proc argument.

ruby/json@92654cd99b

Author: robinetmiller

ext/json/lib/json/common.rb

@@ -662,6 +662,7 @@ def pretty_generate(obj, opts = nil)
   #     when Array
   #       obj.map! {|v| deserialize_obj v }
   #     end
+  #     obj
   #   })
   #   pp ruby
   # Output:
@@ -826,6 +827,7 @@ def unsafe_load(source, proc = nil, options = nil)
   #     when Array
   #       obj.map! {|v| deserialize_obj v }
   #     end
+  #     obj
   #   })
   #   pp ruby
   # Output: