- Update info for weak ETag
- Add info for strong ETag
- Add examples for strong and weak ETags
- Display difference between generated strong and weak ETags strings.

enhance ActiveRecord#substitute_values to loop values just once

Previously `String#to_time` returned the midnight of the current date
in some cases where there was no relavant information in the string.
Now the method returns `nil` instead in those cases.

Fixes #22958.

The native DateTime#<=> implementation can be used to compare instances
with numeric values being considered as astronomical julian day numbers
so we should call that instead of returning nil.

Fixes #24228.

If the test run was interrupted in some way then it left temporary
directories inside of test causing the git worktree to be in a dirty
state. By overriding the run method we can use the block form of
Dir.mktmpdir to ensure that the directories are cleaned up no matter
which way the test run is exited.

The constant reference A::B used to trigger autoloading causes a warning
to be logged about the possible use of :: in a void context so assign it
to the _ variable to prevent the warnings from being triggered.

Update Rails 5.0 release notes

- Removed entry for # Template Collection from release notes.
- Remove duplicate entry for caching Action mailer views.
- Remove duplicate entry for left_outer_joins.

Grammar fixes based on pass over ETag doc changes

remove deprecated `datetime_field` from guide [ci skip]

`datetime_field` was deprecated in 316811b4

[ci skip]

Remove not needed including

Grammer fix in comment: capitalize first word in sentence [ci skip].

Because `DateTime` inherits `Date` and `Date` includes `DateAndTime::Zones`,
`DateTime` not need to include `DateAndTime::Zones` again.

Strong ETag validators

Fixes broken link in 'Ruby on Rails 2.2 Release Notes'

* Introduce `Response#strong_etag=` and `#weak_etag=` and analogous options
  for `fresh_when` and `stale?`. `Response#etag=` sets a weak ETag.

  Strong ETags are desirable when you're serving byte-for-byte identical
  responses that support Range requests, like PDFs or videos (typically
  done by reproxying the response from a backend storage service).
  Also desirable when fronted by some CDNs that support strong ETags
  only, like Akamai.

* No longer strips quotes (`"`) from ETag values before comparing them.
  Quotes are significant, part of the ETag. A quoted ETag and an unquoted
  one are not the same entity.

* Support `If-None-Match: *`. Rarely useful for GET requests; meant
  to provide some optimistic concurrency control for PUT requests.

sanitiser helper may be remove in 5.1, update doc [ci skip]

This reverts commit 7b82e1c7.

This would have removed the ability to reference a schema when using PG

Fix method String#upcase_first

Move `@quoted_{column|table}_names` cache up to the abstract adapter

Deprecate `datetime_field` and `datetime_field_tag` helpers.

Datetime input type was removed from HTML specification.
One can use `datetime_local_field` and `datetime_local_field_tag` instead.

When prepared statements are enabled, the statement cache caches the SQL
directly, including the bind parameters. If a similar query is run later
with prepared statements disabled, we need to use a separate cache
instead of trying to share the same one.

Fixes #24351

Dots have special meaning in most backends (e.g. everything except
SQLite3), as well as most methods that work with table or column names.
This isn't something that we ever explicitly supported, but there's at
least one case of somebody using this (see #24367), so we'll go through a deprecation
cycle as normal.

This issue occured because associations now call `where` directly, and a
dot in the key name for `where` means nested tables. For this fix, we
now pass the table name as a symbol, and do not attempt to expand
symbols containing a dot.

This is a temporary fix. I do not think we should support table names
containing a dot, as it has a special meaning in most backends, as well
as most APIs that involve table names. This commit does not include a
test, as I am going to deprecate table names containing dots in the
following commit.

Fixes #24367

[ci skip] Parameters filter performs regular expression partial matching

Cable message encoding

* Introduce a connection coder responsible for encoding Cable messages
  as WebSocket messages, defaulting to `ActiveSupport::JSON` and duck-
  typing to any object responding to `#encode` and `#decode`.
* Consolidate encoding responsibility to the connection. No longer
  explicitly JSON-encode from channels or other sources. Pass Cable
  messages as Hashes to `#transmit` and rely on it to encode.
* Introduce stream encoders responsible for decoding pubsub messages.
  Preserve the currently raw encoding, but make it easy to use JSON.
  Same duck type as the connection encoder.
* Revert recent data normalization/quoting (#23649) which treated
  `identifier` and `data` values as nested JSON objects rather than as
  opaque JSON-encoded strings. That dealt us an awkward hand where we'd
  decode JSON strings… or not, but always encode as JSON. Embedding
  JSON object values directly is preferably, no extra JSON encoding,
  but that should be a purposeful protocol version change rather than
  ambiguously, inadvertently supporting multiple message formats.

Cable: reconcile default worker pool size with low db conn pool size

using `rails-html-sanitizer` gem still Rails providing strip_tags, strip_links features. May be remove in 5.1

Whack it down from 100 to 4.

Large worker pools means large db connection counts. We aren't set up
for that by default and most apps won't need it out of the box.

We're better off tuning the default worker pool for low traffic, low
resource consumption apps. Those who have higher traffic will scale up
to meet demand.

Make to private the visibility of `_quote` and `_type_cast`