Previously, the cache size of `ActiveSupport::Cache::MemoryStore` was calculated
as the sum of the size of its entries, ignoring the size of keys and any data
structure overhead. This could lead to the calculated cache size sometimes being
10-100x smaller than the memory used, e.g., in the case of small values.

The size of a key/entry pair is now calculated via `#cached_size`:

    def cached_size(key, entry)
      key.to_s.bytesize + entry.size + PER_ENTRY_OVERHEAD
    end

The value of `PER_ENTRY_OVERHEAD` is 240 bytes based on an [empirical
estimation](https://gist.github.com/ssimeonov/6047200) for 64-bit MRI on
1.9.3 and 2.0.

Fixes GH#11512 https://github.com/rails/rails/issues/11512

Extract verbs array from helper to a contant

Fix test name typos

Upgrade guide. Renaming Indexes on tables. [ci skip]

https://github.com/rails/rails/commit/39eef1a565ef02e4dabc0811ef1bf4547ff9a60e#commitcomment-3672522

Closes #11498.

remove duplication in concern_test

Revert "Fix SyntaxError in guides sample code"

This reverts commit f573df32.

The original idea of this documentation was to showcase the feature
where you can remove some only queries attributes with a single
key-value pair.

Thanks @egilburg

[ci skip]

[ci skip]

grammar fix in upgrade documentation

Use latest mysql2.

Fixes #11457

Fixed README link in API

Improve ActiveRecord::QueryMethods#includes docs [ci skip]

It's not immediately clear whether you can pass in multiple relations or
not. After going through the code a bit, I saw that the arguments are
just appended to an array. Also, added nested relations example.

[ci skip]

fixes plugin test for tutorial [ci skip]

[ci skip]

Update bcrypt-ruby stable version to 3.1

Only build the missing_keys array once we have detected that there
actually are missing keys by moving the check to be part of the block
that performs the path substitution.

This should not be a link because
it's creating a link with activesupport README right now

When optimized path helpers were re-introduced in d7014bc7 the test added
in a328f2ff broke but no-one noticed because it wasn't being run by the
test suite.

Fix the test by checking for nil values or empty strings after the args
have been parameterized.

This reverts commit cb1d07e4, reversing
changes made to 754a373e.

When generating an unnamed url (i.e. using `url_for` with an options
hash) we should skip anything other than standard Rails routes otherwise
it will match the first mounted application or redirect and generate a
url with query parameters rather than raising an error if the options
hash doesn't match any defined routes.

Fixes #8018