Bugfix config.action_view.default_form_builder option
Fix documentation for #default

Just a little syntax error I spotted by accident. Cannot pass hash with curly braces without normal parentheses.
Merge pull request #17869 from 2called-chaos/patch-1

Fix documentation for ActionMailer::Base#default [ci skip]
ugh, forgot to add this test to cdd90f39d796986dabf1678b3277b230dbe18961
Remove unused AV/test/fixtures/blog_public

The fixtures were added to support StaticTests in 401cd97 but
those tests were then removed in d5ad92ce.

If Travis CI is happy with this PR, then you can be sure that
those fixtures are not needed anymore.
Remove one AV fixture (duplicate of an AP fixture)

Both ActionPack and ActionView include `test/fixtures/functional_caching/fragment_cached_without_digest.html.erb`.

The [ActionPack file](https://github.com/rails/rails/blob/master/actionpack/test/fixtures/functional_caching/fragment_cached_without_digest.html.erb) is used by the tests.

The [ActionView file](https://github.com/rails/rails/blob/master/actionview/test/fixtures/functional_caching/fragment_cached_without_digest.html.erb) is not: it was introduced in eb23754e when some tests and
fixtures were moved from AP to AV, but no tests in AV uses the fixture.

Long story short: if Travis CI is happy with removing the fixture, you can
be sure that is not needed anymore!
Merge pull request #17866 from bogdan/default-form-builder

Bugfix config.action_view.default_form_builder option
Merge pull request #17872 from claudiob/remove-duplicate-functional-caching-fixture

Remove one AV fixture (duplicate of an AP fixture)
Merge pull request #17871 from claudiob/remove-unused-blog-public-fixtures

Remove unused AV/test/fixtures/blog_public
Silence Minitest for plugin tests.

Fixes https://github.com/rails/rails/issues/17340.

Rails::BacktraceCleaner's silencers are removed to obtain the full
backtrace for all libraries included in the plugin which can be helpful
when debugging errors. However, we will silence traces for Minitest
as it adds noise to the backtrace.