These comments were removed in 8b69f1ee.

Fix a tiny typo and vertical-align some return results in the
ActiveModel::Errors documentation.

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r? @rafaelfranca

This will make easier to applications that rely on having const_missing
hooks in production upgrade to Rails 5.

This option is going to be remove in the future and the default behavior
will be to disable the dependency loading.

- Fixes #25394.

reverts change in previous commit
https://github.com/rails/rails/commit/ea4f0e2

docs should prefer to use `rails` over `rake` in the context of an
application, but in the context of the Rails source this is not the case

The beginning of the note on the :on option is not capitalised correctly.
The :destroy symbol in the after_commit example is unnecessarily wrapped in an array.

@prathamesh-sonpatki

- https://github.com/rails/rails/pull/18288.
- https://github.com/rails/rails/commit/da9038e.
- https://github.com/rails/rails/commit/78dab2a8569408658542e462a957ea5a35aa4679.
- https://github.com/rails/rails/pull/9065.
- https://github.com/rails/rails/pull/18314.
- https://github.com/rails/rails/pull/13434.

- Followup of https://github.com/rails/rails/commit/8b69f1eeba753c38364fb88136b2503480f2de1d.

Link to the more detailed message documentation when using a message option in validations.

- It is also marked as WIP as we are still refining it.

- https://github.com/rails/rails/pull/18721
- https://github.com/rails/rails/pull/11898
- https://github.com/rails/rails/pull/18194
- https://github.com/rails/rails/pull/18225
- https://github.com/rails/rails/pull/18244
- https://github.com/rails/rails/commit/edc2b7718725016e988089b5fb6d6fb9d6e16882
- https://github.com/rails/rails/pull/19686

SSL_set_verify(3) explains:

SSL_VERIFY_FAIL_IF_NO_PEER_CERT
  Server mode: if the client did not return a certificate, the TLS/SSL
handshake is immediately terminated with a "handshake failure" alert.
This flag must
  be used together with SSL_VERIFY_PEER.

  Client mode: ignored

SSL_VERIFY_CLIENT_ONCE
  Server mode: only request a client certificate on the initial TLS/SSL
handshake. Do not ask for a client certificate again in case of a
renegotiation.
  This flag must be used together with SSL_VERIFY_PEER.

  Client mode: ignored

The SMTP connection here uses a OpenSSL socket in client mode,
suggesting invalid/ignored flags is rather misleading.

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it reads a bit awkwardly without it.

Not sure why #25239, but it had good changes, so I'm manually pulling in
the changes.

[Jon Moss, Rajat Bansal]

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`:enum_prefix` and `:enum_suffix` was changed to `:_prefix` and `:_suffix`
in #20999.

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Default worker pool size was changed from 100 to 4 at #24376

Because I can never remember if `collection_singular_ids=` persists
or not (it does).

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- Grammar edits.

Follow up to #17845.