Improve poor security recommendation in docs

As reported in #9960, the current documentation recommends an insecure practice for
key generation from a password (a single round of SHA-256). The modified documentation
uses ActiveSupport::KeyGenerator to perform proper key stretching.
Use `request.fullpath` to build redirect url in `force_ssl`

The `force_ssl` command now builds the redirect url from `request.fullpath`.
This ensures that the format is maintained and it doesn't redirect to a route
that has the same parameters but is defined earlier in `routes.rb`. Also any
optional segments are maintained.

Fixes #7528.
Fixes #9061.
Fixes #10305.
AV Digestor correctly passes format to LookupContext

ActionView::Digestor now passes arguments correctly to
LookupContext::find method. This makes cache digests
respect the format option correctly.

FixtureFinder in tests also changed to reflect this.
Add support for extra options to `force_ssl`

This commit adds support for passing additional url options along
with a :status option and any of the flash-related options to
`redirect_to` (i.e. :flash, :alert & :notice).

Closes #7570.
Merge pull request #10337 from eimermusic/fix_template_digestor_lookup

Fix ActionView::Digestor to correctly pass format to LookupContext

Conflicts:
	actionpack/CHANGELOG.md
Revert "Merge pull request #10337 from eimermusic/fix_template_digestor_lookup"

This reverts commit b4239622afc4f3f73808fd0c97512f3a534e07dd, reversing
changes made to f99ce3c188f5dde57e2ff63e6a22363c62f0a4cd.

Reason: This broke the build
https://travis-ci.org/rails/rails/jobs/6629894
fixes warning in the AR test suite
ActiveRecord -> Active Record
better document `next_week` functionaility closes #9568
Delegation method bug
Add documentation and test to delegation method that make sure we're
aware that when a delegated object is not nil or false and doesn't
respond to the method it will still raise a NoMethodError exception.
Merge pull request #10347 from lellisga/delegation_bug_documentation

Delegation method bug
formatting
Merge pull request #10351 from JonRowe/update_as_date_next_week_to_document_intent

Propose better documentation for ActiveSupports `next_week` functionaility
Merge pull request #9980 from stouset/patch-1

Improve poor security recommendation in docs

[ci skip]
Module#delegate checks nilness rather that falsehood if :allow_nil is true, and avoids multiple evaluation of the target method

Notes:

1) I hope nilness is a word.

2) See rationale for avoiding multiple evaluation in a comment in the patch, credit goes to @jeremy for pointing out this gotcha in the existing implementation.

3) Embeds a little joke dedicated to @pixeltrix (it could be worse! :D).

References #10347.
adding test for the symbol refs
Don't reprocess the options hash on every request
pass over the code comments

* Highlights the requirement of an attributes method.
* Removes some details that depend on the implementation of the class including the module.
* Applies guidelines here and there.
fixes a test, and explains why AR::AttributeMethods checks defined?(@attributes) in some places