Refactor join_keys to remove complex conditionals

These methods mutate the path variable/argument so there is no need
to reassign it every time.

Pushing conditionals down to through reflection

Only the through association needs the part of this conditional
that deals with belongs to and polymorphic? so that can be pushed
down into the ThroughReflection reducing the conditionals.

Remove conditional because we can delegate join keys to source reflection

Remove need for source_macro checking

By adding join_id_for to the other reflections we remove the need
to cehck against the source_macro and can reduce the conditioanl
from the original join_id_for(owner)

Using polymorphism instead of testing the source_macro

This case statement in join_association is almost exactly the same
as the original join_keys code. Testing taht theory by creating a
new join_dependency_keys(assoc_klass) method.

Refactor join_keys further to be more concise

Fixed format of "#:nodoc:" to "# :nodoc:" where I added them to this
file.

Merge pull request #16351 from eileencodes/finish-refactoring-macro-to-eliminate-checking-against-symbols

Redefine macro checks for reflections

This is not storying the RouteSet instance anywhere as the other
examples in the file, so no need to use #tap.

Add tests to ensure default proc is used when `HashWithIndifferentAccess' is initialized with a block

Add tests to ensure default proc is used when `HashWithIndifferentAccess' is initialized with a block

Raise a descriptive error if non-positive integer passed to in_groups_of

This is more consistent than the current behaviour of raising a
`ZeroDivisionError: divided by 0` error when 0 is given, which can be
non-obvious especially if `in_groups_of` is part of a longer chain of
methods.

The negative case was ok - "ArgumentError: invalid slice size" - but
this error is clearer still.

The message passed to Minitest's assert_raise is used as output in case
the assertion fails, but we can test against the exact message by using
the actual exception object that is returned from the assert_raise call.

Removed unnecessary call to 'convert_key' in 'HashWithIndifferentAccess#to_hash'

We are using blocks here so we have access to the environment around
them, no need for globals.

every call to default_resources_path_names allocates a new hash, no need
to dup

this makes scope rollback much easier

All the keys are already Strings by virtue of being a HashWithIndifferentAccess.

Now that we define the macro on the reflection type we no longer
need to check `macro == :what` on each type for `belongs_to?` or
`has_one?` etc. These now default to false unless it's defined
in the reflection class.

Reuse existing belongs_to? method to check macros

We don't need to do `:belongs_to == macro` anymore becasue we
have a `belongs_to?` method. I didn't find this being used
anywhere for `has_one?` or `collection?` since they were already
fixed.

just ask whether or not the route is defined

we can `super` in to the previous implementation.

we already know what helpers are path helpers, so just iterate through
that list and define the helpers with warnings

this lets us avoid hard coding a regexp for separating path and url
helpers in the clear! method.

Deprecate `*_path` methods in mailers