ActiveJob -> Active Job [ci skip]

See http://guides.rubyonrails.org/api_documentation_guidelines.html#wording

activejob/lib/active_job/gem_version.rb

 module ActiveJob
-  # Returns the version of the currently loaded ActiveJob as a <tt>Gem::Version</tt>
+  # Returns the version of the currently loaded Active Job as a <tt>Gem::Version</tt>
   def self.gem_version
     Gem::Version.new VERSION::STRING
   end

activejob/lib/active_job/version.rb

 require_relative 'gem_version'
 
 module ActiveJob
-  # Returns the version of the currently loaded ActiveJob as a <tt>Gem::Version</tt>
+  # Returns the version of the currently loaded Active Job as a <tt>Gem::Version</tt>
   def self.version
     gem_version
   end

guides/source/active_job_basics.md

@@ -203,7 +203,7 @@ is integrated with Action Mailer so you can easily send emails asynchronously:
 # If you want to send the email now use #deliver_now
 UserMailer.welcome(@user).deliver_now
 
-# If you want to send the email through ActiveJob use #deliver_later
+# If you want to send the email through Active Job use #deliver_later
 UserMailer.welcome(@user).deliver_later
 ```