Tiny follow-up to #16999 [ci skip]

* Fix a typo
* Remove references to Rails version
* Remove an extra whitespace

activejob/lib/active_job/queue_adapters/qu_adapter.rb

@@ -10,7 +10,7 @@ module ActiveJob
     # The advantages of Qu are: Multiple backends (redis, mongo), jobs are
     # requeued when worker is killed, resque-like API.
     #
-    # Read more about Que {here}[https://github.com/bkeepers/qu].
+    # Read more about Qu {here}[https://github.com/bkeepers/qu].
     #
     # To use Qu set the queue_adapter config to +:qu+.
     #

activejob/lib/active_job/queue_adapters/sidekiq_adapter.rb

@@ -6,8 +6,8 @@ module ActiveJob
     #
     # Simple, efficient background processing for Ruby. Sidekiq uses threads to
     # handle many jobs at the same time in the same process. It does not
-    # require Rails but will integrate tightly with Rails 3/4 to make
-    # background processing dead simple.
+    # require Rails but will integrate tightly with it to make background
+    # processing dead simple.
     #
     # Read more about Sidekiq {here}[http://sidekiq.org].
     #

guides/source/active_job_basics.md

@@ -99,7 +99,7 @@ If no adapter is set, the job is immediately executed.
 
 ### Backends
 
-Active Job has  built-in adapters for multiple queueing backends (Sidekiq,
+Active Job has built-in adapters for multiple queueing backends (Sidekiq,
 Resque, Delayed Job and others). To get an up-to-date list of the adapters
 see the API Documentation for [ActiveJob::QueueAdapters](http://api.rubyonrails.org/classes/ActiveJob/QueueAdapters.html).