Fix documentation for enqueue_after_transaction_commit

Correct some grammar and update the framework defaults documentation
from use `true` and `false` to `:never` and `:default`.

guides/source/configuring.md

@@ -2768,9 +2768,13 @@ end
 Controls whether Active Job's `#perform_later` and similar methods automatically defer
 the job queuing to after the current Active Record transaction is committed.
 
-It can be set to `:never` to never defer the enqueue, to `:always` always defer
-the enqueue, or to `:default` to let the queue adapter define if it should be defered
-or not. Active Job backends that use the same database than Active Record as a queue,
+It can be set to:
+
+* `:never` - Never defer the enqueue.
+* `:always` - Always defer the enqueue.
+* `:default` - Let the queue adapter define the behaviour.
+
+Active Job backends that use the same database as Active Record as a queue,
 should generally prevent the deferring, and others should allow it.
 
 Example:
@@ -2783,8 +2787,8 @@ end
 ```
 
 In this example, if the configuration is set to `:never`, the job will
-be enqueued immediately, even thought the `Topic` hasn't been committed yet.
-Because of this, if the job is picked up almost emmediately, or if the
+be enqueued immediately, even though the `Topic` hasn't been committed yet.
+Because of this, if the job is picked up almost immediately, or if the
 transaction doesn't succeed for some reason, the job will fail to find this
 topic in the database.
 

railties/lib/rails/generators/rails/app/templates/config/initializers/new_framework_defaults_7_2.rb.tt

@@ -19,12 +19,14 @@
 #     NewTopicNotificationJob.perform_later(topic)
 #   end
 #
-# In this example, if `enqueue_after_transaction_commit` is `false` the job will
-# be enqueued immediately, even thought the `Topic` hasn't been committed yet.
-# Because of this, if the job is picked up almost emmediately, it will fail to
-# find this topic in the databse.
-# With `enqueue_after_transaction_commit = true`, the job will be actually enqueued
-# after the transaction has been committed.
+# In this example, if the configuration is set to `:never`, the job will
+# be enqueued immediately, even though the `Topic` hasn't been committed yet.
+# Because of this, if the job is picked up almost immediately, or if the
+# transaction doesn't succeed for some reason, the job will fail to find this
+# topic in the database.
+#
+# If `enqueue_after_transaction_commit` is set to `:default`, the queue adapter
+# will define the behaviour.
 #
 # Note: Active Job backends can disable this feature. This is generally used by
 # backends that use the same database than Active Record as a queue, hence they