Fix AS::TimeWithZone#as_json docs

According to 28ab79d7

activesupport/lib/active_support/time_with_zone.rb

@@ -146,12 +146,12 @@ def xmlschema(fraction_digits = 0)
     # to +false+.
     #
     #   # With ActiveSupport::JSON::Encoding.use_standard_json_time_format = true
-    #   Time.utc(2005,2,1,15,15,10).in_time_zone.to_json
-    #   # => "2005-02-01T15:15:10Z"
+    #   Time.utc(2005,2,1,15,15,10).in_time_zone("Hawaii").to_json
+    #   # => "2005-02-01T05:15:10.000-10:00"
     #
     #   # With ActiveSupport::JSON::Encoding.use_standard_json_time_format = false
-    #   Time.utc(2005,2,1,15,15,10).in_time_zone.to_json
-    #   # => "2005/02/01 15:15:10 +0000"
+    #   Time.utc(2005,2,1,15,15,10).in_time_zone("Hawaii").to_json
+    #   # => "2005/02/01 05:15:10 -1000"
     def as_json(options = nil)
       if ActiveSupport::JSON::Encoding.use_standard_json_time_format
         xmlschema(3)