The `FactoryBot` module has a mixture of methods that are meant for use
by people using the library, and methods that are meant only for
internal use. The methods meant for internal use are cluttering the
documentation, and may be confusing to users.
This change was prompted by [#1258]. Rather than introduce yet another
public method on `FactoryBot` meant only for internal use,
we can introduce a `FactoryBot::Internal` module,
and avoid generating documentation for that module.
The `FactoryBot::Internal.register_inline_sequence` method in [#1258]
will need access to the configuration instance, so this PR moves that
into `FactoryBot::Internal`. Eventually I plan to deprecate
`FactoryBot.configuration` and `FactoryBot.reset_configuration`, and to
move more of the `FactoryBot` methods into `FactoryBot::Internal`, but I
would rather hold off on all that until the dust settles on the 5.0
release.
[#1258]: https://github.com/thoughtbot/factory_bot/pull/1258
FactoryBot::Syntax::Methods was missing some documentation on
the *_pair methods. This adds in the documentation and
corresponding method directives.
Further, add the missing &block parameter to the existing *_list directives.
We decided not to included documentation for the `null` strategy,
since this strategy is used internally, and only returns `nil`. There isn't
much point in documenting it and making it available.
