Update AR reload doc for the case of manually set primary key attribute [ci skip]
Merge pull request #12418 from makaroni4/fix/ar_reload_doc_12101

Update AR reload doc for the case of manually set primary key attribute [ci skip]
improving `reload` doc wording. #12418 [ci skip]
unify `Fixes` notes in AR changelog. [ci skip].
Added activemodel as a explicit dependency

As we have other dependency explicitly here
it's fine to add activemodel as well
Merge pull request #12426 from arunagw/added_activemodel_in_railsgemspec

Added activemodel as a explicit dependency
decouple define_callback from the instance
name is on the reflection, so just use the reflection
Adds the Rails maintenance policy to the Guides

[ci skip]
push constructable? on to the reflection
association builder is no longer needed for counter cache, so remove it
Running all isolated test for actionview

1. fix name for activerecord directory
2. Added actionpack directory to run tests
Merge pull request #12428 from arunagw/running_isolated_test_av

Running all isolated test for actionview
Merge pull request #12171 from matiaskorhonen/adds-maintenance-policy-to-guides

Adds the Rails maintenance policy to the Guides
use the information on the reflection to determine whether callbacks should be added
valid_options doesn't depend on the instance, so push it to the class
add_before_destroy_callbacks doesn't depend on the instance, so push it
to the class.
decouple belongs_to callback definition from the builder instance.

All the information is on the reflection, so just get it there.
cache the name and options on the stack
get the name from the reflection