[ci skip] Add documentation to Parameter Encoding

Fix unsafe query generation risk.

Redo of CVE-2012-2660, CVE-2012-2694 and CVE-2013-0155

CVE-2016-6317

Creating a new Topic class instead of class_eval for the existing one

Fix warning: ambiguous first argument

Many helpers mark content as HTML-safe without escaping double quotes -- including `sanitize`. Regardless of whether or not the attribute values are HTML-escaped, we want to be sure they don't include double quotes, as that can cause XSS issues. For example: `content_tag(:div, "foo", title: sanitize('" onmouseover="alert(1);//'))`

CVE-2016-6316

since it affects another test `ReflectionTest#test_read_attribute_names`

Address #26099

add missing require rake

In ff8035df, require rake is deferred.
Therefore, it is necessary to require rake even `Engine::CommandsTasks.

Fix actionview test failure

Caused by #26092.

Minor doc fix related to ActiveModel::SecurePassword [ci skip]

Thinking .. relative to files is not natural, we are used
to think "parent of a directory", and we have __dir__
nowadays.

Add documentation for `http_cache_forever`. [ci skip]

Allow specifying encoding of parameters by action

Fix a NoMethodError schema_statements.rb

In c546a2b0 parameter handling in AC test cases was changed to
round tripping through encoders/decoders so that they matched
reality and in 0adb8f8f the old methods were removed but the
`html_format?` method was overlooked.

If you call `remove_index` with wrong options, say a type, like I did,
you get:

```
== 20160810072541 RemoveUniqueIndexOnGoals: migrating =========================
-- remove_index(:goal, {:coulmn=>:kid_id, :unique=>true})
rails aborted!
StandardError: An error has occurred, this and all later migrations canceled:

undefined method `ArgumentError' for #<ActiveRecord::ConnectionAdapters::PostgreSQLAdapter:0x007fb7dec91b28>
```

What happened is that I mistyped column (coulmn) and got a
`NoMethodError`, because of a missing comma during the raise. This made
Ruby think we're calling the method `ArgumentError`.

At GitHub we need to handle parameter encodings that are not UTF-8. This
patch allows us to specify encodings per parameter per action.

Fix broken alignments caused by auto-correct commit 411ccbda

Hash syntax auto-correcting breaks alignments. 411ccbda

Document know limitation about using `references` in conjunction with custom select clauses [ci skip]

Document know limitation about using `references` in conjunction with eager loading causing it to ignore custom select clauses.

[ci skip]

Fixes #24314

Add link to 'Pry' in debugging guide [ci skip]

update list of rescue_responses default [ci skip]

Follow up to fe859a54

Use `FETCH FIRST` for Oracle12 and test `ROWNUM <=` for Oracle 11g or older version to test sql limit behavior

also test `ROWNUM <=` for Oracle 11g or older version of Oracle and Oracle visitor
Oracle 12c database and Arel Oracle12 visitor supports better top N query.

This code has too much duplication and the rationale for the concatenation
may not be obvious to the reader. You define the ones at class-level, explain
why does the code concatenates there, and then the convenience ones at
instance-level just delegate.

Fix `thread_mattr_accessor` share variable superclass with subclass

A few have been left for aesthetic reasons, but have made a pass
and removed most of them.

Note that if the method `foo` returns an array, `foo << 1`
is a regular push, nothing to do with assignments, so
no self required.

Some case expressions remain, need to think about those ones.