Move Rack::Cache after AD::Static in the stack
Add `rake test:all`, `rake test:all:db` to guide

[ci skip]
[ci skip] Removing some gender sensitive object pronouns
Update API docs guidelines with reference about gender neutral pronouns
Add examples for gender neutral pronouns
Merge pull request #13130 from gja/master

Removing some gender sensitive object pronouns
Try to escape each part of a path redirect route correctly

A path redirect may contain any and all parts of a url which have different
escaping rules for each part. This commit tries to escape each part correctly
by splitting the string into three chunks - path (which may also include a host),
query and fragment; then it applies the correct escape pattern to each part.

Whilst using `URI.parse` would be better, unfortunately the possible presence
of %{name} parameters in the path redirect string prevents us from using it so
we have to use a regular expression instead.

Fixes #13110.
Cleanups in API docs: his => their
Update active_record_querying.md

he or she => they
Merge pull request #12365 from jbaudanza/reorder

Move Rack::Cache after ActionDispatch::Static in the middleware stack
`ActionView::MissingTemplate` for partials includes underscore.

Missing partial folder/_partial instead of folder/partial.

Closes #13002.
Typo and grammatical fixes [ci skip]
Merge pull request #11466 from jetthoughts/updated_tesing_guides

Fix `rake test` description in the guides [ci skip]
Merge pull request #13117 from akshay-vishnoi/typo

Typo and grammatical fixes [ci skip]
`mail()` without arguments is a getter for the current mail.

This behavior is documented in our guides (http://edgeguides.rubyonrails.org/action_mailer_basics.html#action-mailer-callbacks)
but was broken in the past. This commit short curcuits
the `mail` method if:

  1. mail() was previously called
  2. no headers are passed
  3. no block is passed

Closes #13090.

/cc @pixeltrix
Introduce a context for rendering fixtures ERB.

Fixture files are passed through an ERB renderer before being read as
YAML. The rendering is currently done in the context of the main object,
so method definitons leak into other fixtures, and there is no clean
place to define fixture helpers.

After this commit, the ERB renderer will use a new subclass of
ActiveRecord::FixtureSet::RenderContext each time a fixture is rendered.