emphasize that callbacks are called in destroy_all

Cleaned up rdoc a bit emphasizing that callbacks are called. Also
removed the stress on the fact that records are always removed.

If callbacks return false then records will not be deleted.

activerecord/lib/active_record/associations/collection_association.rb

@@ -237,11 +237,11 @@ def delete(*records)
         end
       end
 
-      # Destroy +records+ and remove them from this association calling
-      # +before_remove+ and +after_remove+ callbacks.
+      # Deletes the +records+ and removes them from this association calling
+      # +before_remove+ , +after_remove+ , +before_destroy+ and +after_destroy+ callbacks.
       #
-      # Note that this method will _always_ remove records from the database
-      # ignoring the +:dependent+ option.
+      # Note that this method removes records from the database ignoring the
+      # +:dependent+ option.
       def destroy(*records)
         records = find(records) if records.any? { |record| record.kind_of?(Fixnum) || record.kind_of?(String) }
         delete_or_destroy(records, :destroy)

activerecord/lib/active_record/associations/collection_proxy.rb

@@ -422,9 +422,9 @@ def delete_all
         @association.delete_all
       end
 
-      # Deletes the records of the collection directly from the database.
-      # This will _always_ remove the records ignoring the +:dependent+
-      # option.
+      # Deletes the records of the collection directly from the database
+      # ignoring the +:dependent+ option. It invokes +before_remove+,
+      # +after_remove+ , +before_destroy+ and +after_destroy+ callbacks.
       #
       #   class Person < ActiveRecord::Base
       #     has_many :pets