Link rescue_from from modules including Rescuable

Also add some additional words to make it clear that the modules also
implement handling the exceptions configured with rescue_from, because
it was not immediately clear that happened without reading the code.

actionmailbox/lib/action_mailbox/base.rb

@@ -57,7 +57,8 @@ module ActionMailbox
   # complete, the status is changed to +delivered+. If a bounce is triggered, then +bounced+. If an unhandled
   # exception is bubbled up, then +failed+.
   #
-  # Exceptions can be handled at the class level using the familiar +Rescuable+ approach:
+  # Exceptions can be handled at the class level using the familiar
+  # ActiveSupport::Rescuable approach:
   #
   #   class ForwardsMailbox < ApplicationMailbox
   #     rescue_from(ApplicationSpecificVerificationError) { bounced! }

actionmailer/lib/action_mailer/rescuable.rb

@@ -3,8 +3,10 @@
 module ActionMailer # :nodoc:
   # = Action Mailer \Rescuable
   #
-  # Provides +rescue_from+ for mailers. Wraps mailer action processing,
-  # mail job processing, and mail delivery.
+  # Provides
+  # {rescue_from}[rdoc-ref:ActiveSupport::Rescuable::ClassMethods#rescue_from]
+  # for mailers. Wraps mailer action processing, mail job processing, and mail
+  # delivery to handle configured errors.
   module Rescuable
     extend ActiveSupport::Concern
     include ActiveSupport::Rescuable

actionpack/lib/action_controller/metal/rescue.rb

@@ -3,9 +3,10 @@
 module ActionController # :nodoc:
   # = Action Controller \Rescue
   #
-  # This module is responsible for providing +rescue_from+ helpers
-  # to controllers and configuring when detailed exceptions must be
-  # shown.
+  # This module is responsible for providing
+  # {rescue_from}[rdoc-ref:ActiveSupport::Rescuable::ClassMethods#rescue_from]
+  # to controllers, wrapping actions to handle configured errors, and
+  # configuring when detailed exceptions must be shown.
   module Rescue
     extend ActiveSupport::Concern
     include ActiveSupport::Rescuable

activejob/lib/active_job/exceptions.rb

@@ -100,9 +100,10 @@ def discard_on(*exceptions)
       end
     end
 
-    # Reschedules the job to be re-executed. This is useful in combination
-    # with the +rescue_from+ option. When you rescue an exception from your job
-    # you can ask Active Job to retry performing your job.
+    # Reschedules the job to be re-executed. This is useful in combination with
+    # {rescue_from}[rdoc-ref:ActiveSupport::Rescuable::ClassMethods#rescue_from].
+    # When you rescue an exception from your job you can ask Active Job to retry
+    # performing your job.
     #
     # ==== Options
     # * <tt>:wait</tt> - Enqueues the job with the specified delay in seconds

activejob/lib/active_job/execution.rb

@@ -4,6 +4,12 @@
 require "active_job/arguments"
 
 module ActiveJob
+  # = Active Job \Execution
+  #
+  # Provides methods to execute jobs immediately, and wraps job execution so
+  # that exceptions configured with
+  # {rescue_from}[rdoc-ref:ActiveSupport::Rescuable::ClassMethods#rescue_from]
+  # are handled.
   module Execution
     extend ActiveSupport::Concern
     include ActiveSupport::Rescuable