Merge pull request #16756 from huoxito/dont-mess-railties-default-order

Dont mess with default order engines load (4.1.6.rc1 regression)
Merge pull request #16775 from kaspth/ship-secure-sanitizer

Ship with rails-html-sanitizer instead.
Active Job refactoring
Merge pull request #16787 from cristianbica/fix-globalid-deserialization

[Active Job] Try to deserialize with GlobalID only strings and globalids
Methods are not duplicable.
Merge pull request #16795 from Peeja/methods-are-not-duplicable

Methods are not duplicable.
Add support for ARIA attributes in tags
Merge pull request #16796 from ARIATeam/aria

Add support for ARIA attributes in tags
Extract data/aria attribute prefixes to a constant
code gardening in ActionController::Renderers

* Renames _handle_render_options to _render_to_body_with_renderer, which is more
  intention-revealing.

* The name of the dynamically generated method for a renderer with key :js was
  "_render_option_js".

  That name is too weak. :js is an option if you see the render argument as just
  a generic options hash, but in the context of renderers that's the renderer
  key, is what identifies the renderer.

  Now "_render_with_renderer_js" is generated instead, which is crystal clear.

* The name of the dynamically generated method for the renderer was constructed
  using string literals in a few places. That is now encapsulated in a method.

* Since we were on it, also removed a couple of redundant selfs.
'Reversible' ->active_record_migrations [ci skip]

Reversible method documentation moved from migrations.md  to active_record_migrations.md
Rename remaining :in / :at to :wait / :wait_until
[ci skip] Fix typo in rails guide for routing
get rid of shadowing warning when running tests AR and railtie tests.

Warning looked like this:

```
/Users/senny/Projects/rails/activerecord/lib/active_record/associations/association_scope.rb:142: warning: shadowing outer local variable - reflection
```
build fix, we have to reset the RACK_ENV as well.

This is a follow-up to ded17a4 to get the build passing on Travis.
As Travis has `ENV["RACK_ENV"]` set to `test` we need to reset that as well.
Enums shouldn't ruin people's anniversaries

Added a few more methods on Module/Class to the dangerous class methods
blacklist. (Technically, allocate and new are already protected currently because
we happen to redefine them in the current implantation.)

Closes #16792
Merge pull request #16799 from rramsden/fix-typo

[ci skip] Fix typo in rails guide for routing
Follup to PR #16762

Remove chain from parameters, it's no longer needed since chain and i
are being passed via next_reflection

Change name of `reflection` to `owner_reflection` because of shadow
variable warning. The last reflection will always be the owner.
Merge pull request #16797 from eileencodes/refactor-add_constraints-followup-to-16762

Followup to PR #16762
Always add lambda to scope chain to eliminate branch in eval_scope

We convert all other scopes to lambda's so it makes sense that we should
always returns a lambda on a ThroughReflection as well. This eliminates
the need to check if the scope is a Relation.