[ci skip] Consolidate docs for `take`

Add docs on what happens when a numerical argument is provided to take.

Since `take!` behaves exactly the same way but can raise an argument we can consolidate it in the `take` section.
[ci skip] Consolidate docs for `last`

Add docs on what happens when a numerical argument is provided to last.

Since `last!` behaves exactly the same way but can raise an argument we can consolidate it in the `last` section.
[ci skip] Consolidate docs for `find`

Put all options for overloading `find` in one section
[ci skip] Doc ability to chain in `find_each`

Also use appropriate mailer syntax in the `find_each` block.
[ci skip] Fix doc for except

The example showed is `except`, however the method "documented" is `unstop`. Fix to align the docs to the example.
[ci skip] remove invalid code from docs
Add punctuation and fix capitalization in Getting Started guide

Fix more small grammar mistakes in the [Getting Started guide](http://edgeguides.rubyonrails.org/getting_started.html#security), in sections 9 and 10.

Specifically, within sections 9.1 “Basic Authentication”, 9.2 “Other Security Considerations”, and 10 “What's Next?”.

“Rails Guides” is generally capitalized on the site, including on the linked page and in the title of the site, so I capitalized it.

“The” is not part of the name of the Ruby on Rails Security Guide – “The” is not in the title on that page.

And I added a missing period and a missing colon at the ends of two sentences.
[ci skip] Fix router option reference in 4.2 release notes.
Merge pull request #15964 from JuanitoFatas/doc/patch-01

[ci skip] Fix router option reference in 4.2 release notes.
Merge pull request #15963 from roryokane/getting-started-guide-fix-grammar

Add punctuation and fix capitalization in Getting Started guide
Merge pull request #15962 from sgrif/sg-types-for-defaults

Always pass a column with a cast_type to quote
Merge pull request #15961 from mckramer/patch-1

Rename options param of #time_ago_in_words to match API change
Quick pass through Active Support and guides CHANGELOG

[ci skip]
Tiny documentation fixes [ci skip]
Don't encourage usage of `columns_hash`

As discussed in https://github.com/plataformatec/simple_form/pull/1094,
we should not encourage usage of `columns_hash`, and instead provide an
alternate method to determine whether or not an attribute exists.

The language `attribute` was chosen over `column` since these are in the
`AttributeMethods` module.
Use the type object for sending JSON to the database
Add `Hash#map_values` to ActiveSupport

Didn't get a chance to convert existing code, I'll skim through the code
base to make use of this later this afternoon.
Merge pull request #15819 from sgrif/sg-hash-map-values

Add `Hash#map_values` to ActiveSupport to simplify a common pattern
Simplify creation of default attributes on AR instance

`AttributeSet#dup` has all the behavior we need.
Merge pull request #15979 from sgrif/sg-json-quoting

Use the type object for sending JSON to the database