Merge pull request #26534 from Neodelf/new_branch_name

[ci skip] Fixed commas according to Oxford comma in rdoc and guides

actionview/lib/action_view/helpers/date_helper.rb

@@ -303,7 +303,7 @@ def date_select(object_name, method, options = {}, html_options = {})
       #   # the sunrise attribute.
       #   time_select("article", "start_time", include_seconds: true)
       #
-      #   # You can set the <tt>:minute_step</tt> to 15 which will give you: 00, 15, 30 and 45.
+      #   # You can set the <tt>:minute_step</tt> to 15 which will give you: 00, 15, 30, and 45.
       #   time_select 'game', 'game_time', {minute_step: 15}
       #
       #   # Creates a time select tag with a custom prompt. Use <tt>prompt: true</tt> for generic prompts.

activesupport/lib/active_support/time_with_zone.rb

@@ -133,7 +133,7 @@ def zone
       period.zone_identifier.to_s
     end
 
-    # Returns a string of the object's date, time, zone and offset from UTC.
+    # Returns a string of the object's date, time, zone, and offset from UTC.
     #
     #   Time.zone.now.inspect # => "Thu, 04 Dec 2014 11:00:25 EST -05:00"
     def inspect

guides/source/active_record_querying.md

@@ -50,7 +50,7 @@ class Role < ApplicationRecord
 end
 ```
 
-Active Record will perform queries on the database for you and is compatible with most database systems, including MySQL, MariaDB, PostgreSQL and SQLite. Regardless of which database system you're using, the Active Record method format will always be the same.
+Active Record will perform queries on the database for you and is compatible with most database systems, including MySQL, MariaDB, PostgreSQL, and SQLite. Regardless of which database system you're using, the Active Record method format will always be the same.
 
 Retrieving Objects from the Database
 ------------------------------------

guides/source/engines.md

@@ -184,7 +184,7 @@ end
 By inheriting from the `Rails::Engine` class, this gem notifies Rails that
 there's an engine at the specified path, and will correctly mount the engine
 inside the application, performing tasks such as adding the `app` directory of
-the engine to the load path for models, mailers, controllers and views.
+the engine to the load path for models, mailers, controllers, and views.
 
 The `isolate_namespace` method here deserves special notice. This call is
 responsible for isolating the controllers, models, routes and other things into

guides/source/layouts_and_rendering.md

@@ -749,7 +749,7 @@ When Rails renders a view as a response, it does so by combining the view with t
 
 ### Asset Tag Helpers
 
-Asset tag helpers provide methods for generating HTML that link views to feeds, JavaScript, stylesheets, images, videos and audios. There are six asset tag helpers available in Rails:
+Asset tag helpers provide methods for generating HTML that link views to feeds, JavaScript, stylesheets, images, videos, and audios. There are six asset tag helpers available in Rails:
 
 * `auto_discovery_link_tag`
 * `javascript_include_tag`

railties/lib/rails/engine.rb

@@ -337,7 +337,7 @@ module Rails
   # == Loading priority
   #
   # In order to change engine's priority you can use +config.railties_order+ in the main application.
-  # It will affect the priority of loading views, helpers, assets and all the other files
+  # It will affect the priority of loading views, helpers, assets, and all the other files
   # related to engine or application.
   #
   #   # load Blog::Engine with highest priority, followed by application and other railties

railties/lib/rails/paths.rb

@@ -30,7 +30,7 @@ module Paths
     #   root["config/routes"].inspect # => ["config/routes.rb"]
     #
     # The +add+ method accepts the following options as arguments:
-    # eager_load, autoload, autoload_once and glob.
+    # eager_load, autoload, autoload_once, and glob.
     #
     # Finally, the +Path+ object also provides a few helpers:
     #