This reverts commit faeb33dc.

Reason: Code changes can't be done on docrails

remove outdated docs

Fix FileStore#cleanup to no longer rely on missing each_key method

Enabled quirks mode on JSON.parse, fixes broken test in af9caae9

It turns out that ActionPack depends on the decoder to parse JSON
"fragments" (e.g. '"a string"', '1', 'null', etc), so we need to
enable quirks mode on JSON.parse. Also added coverage on the decoder
side to prevent regression.

[ci skip]

Cleanup: replace String concatenation by joining for excerpt helper

Update 4_0_release_notes.md

Active support --> Deprecations Code highlighted.

Added quotes when defining the precision for the `decimal` fields

Remove unused raw email fixtures

before:

```bash
$ rails generate migration AddDetailsToProducts price:decimal{5,2} supplier:references{polymorphic}
```

after:

```bash
$ rails generate migration AddDetailsToProducts 'price:decimal{5,2}' supplier:references{polymorphic}
```

The tests that used the raw_email_* fixtures were removed in d500ad3f

Replace JSON.load with JSON.parse

sense.  Let's load the object to ensure it's an array and count the
array.

At the point we want to add the reflection we already know the
reflection is of the AggregateReflection type so we can call a specific
method

Since we are dealing with untrusted user input, we should not be
using JSON.load. According to the docs[1]:

BEWARE: This method is meant to serialise data from trusted user
input, like from your own database server or clients under your
control, it could be dangerous to allow untrusted users to pass
JSON sources into it. The default options for the parser can be
changed via the ::load_default_options method.

[1] http://www.ruby-doc.org/stdlib-2.0/libdoc/json/rdoc/JSON.html#method-i-load

Oops, I should had run the tests

This is not valid anymore after 08477a65

When the adapter is with prepared statement disabled and the binds array
is not empty the connection adapter will try to set the binds values and
will fail. Now we are checking if the adapter has the prepared statement
disabled.

Fixes #12023

Perf: avoid dupes add fallback logic for coders

Reduce Duration#inspect to a single series of transformations

Avoid empty transaction from setting has_one association on new record.

Conflicts:
	activerecord/CHANGELOG.md

Reduce allocations when extracting AR models

Relation#merge should not lose readonly(false) flag.

This reverts commit ba040733.

remove sentence err

* eliminates need for temp Hash

Also added a couple of examples to DurationTest to specify:

* duration can be defined with units out of order e.g.
  1.month + 1.year + 1.second + 1.day
* equality with a Fixnum works regardless of which operand is on which
  side of the operator