private method doesn't work for singleton methods defined this way
Use short-form for the scaffold render calls and drop the needless test
Dont encourage aliases now that we have variants
Dont abbreviate that which needs no abbreviation
Updates the maintenance policy with new Rails versions
Merge pull request #14647 from matiaskorhonen/updates-maintenance-policy

Updates the maintenance policy with new Rails versions
new CHANGELOGs entries are in the top [ci skip]
Fixed problem where `1.day.eql?(1.day)` is false

This fixes:
    1.second.eql?(1.second) #=> false

The new `eql?` requires that `other` is an `ActiveSupport::Duration`.
This requirement makes `ActiveSupport::Duration`'s behavior consistent
with other numeric types in Ruby.

    1.eql?(1.0) #=> false
    1.0.eql?(1) #=> false

    1.second.eql?(1) #=> false (was true)
    1.eql?(1.second) #=> false

    { 1 => "foo", 1.0 => "bar" }
    #=> { 1 => "foo", 1.0 => "bar" }

    { 1 => "foo", 1.second => "bar" }
    # now => { 1 => "foo", 1.second => "bar" }
    # was => { 1 => "bar" }

And though the behavior here hasn't changed, for reference:

    1 == 1.0 #=> true
    1.0 == 1 #=> true

    1 == 1.second #=> true
    1.second == 1 #=> true
Guides: minor typo fixed [ci skip]
Merge pull request #14652 from Emily/duration_eqls

Fixed problem where `1.day.eql?(1.day)` is false
Merge pull request #14653 from vdmgolub/patch-1

Guides: minor typo fixed in Asset Pipeline guide
Expand explanation of how to set secrets.yml. [ci skip]
upgrading section for 4.1 is no longer WIP. [ci skip]
Merge pull request #14654 from Alamoz/secret_key

Expand explanation of how to set secrets.yml.
depend_on_asset is not required anymore on sprockets-rails 2.1.2
Add missing require so requiring `active_support/cache` works again.
Merge pull request #14667 from lucasmazza/require-per-thread-registry

Add missing require so requiring `active_support/cache` works again.
Avoid URI parsing

This parsing is unecessary once the Request object already has the
needed information.
Merge pull request #14665 from andrielfn/avoid-uri-parsing

Avoid URI parsing
The `source` option for `has_many => through` should accept String
values.

With the changes introduced by 16b70fddd4dc7e7fb7be108add88bae6e3c2509b
it was expecting the value to be a Symbol, while it could be also a
String value.