[ci skip] Fix doc for javascript_helper
Correct Bundler link [ci skip]
Merge pull request #15620 from aditya-kapoor/correct-bundler-link

Correct Bundler link [ci skip]
No need to decorate columns twice

We never want result types to override column types, and
`decorate_columns` can only affect column types. No need to go through
the decoration multiple times, we can just exclude the column types from
the result types instead.
Merge pull request #15619 from aditya-kapoor/fix-js-doc

[ci skip] Fix doc for javascript_helper
Merge pull request #15621 from sgrif/sg-column-type-decorations

No need to decorate columns twice
remove deprecated code. Rely on `describe` provided by minitest
begin refactoring add_constraints by moving join keys

add_constraints is complicated and difficult to read. This is the
beginning of a long process of refactoring this code. First step:
moved the join keys out of AssociationScope and into reflection.

We then don't need to call `reflection` because now reflection is
`self`.

`foreign_key` must be named something else because reflection already has a
`foreign_key` method and when passed into `JoinKeys` it was getting the
wrong assignment. `reflection_foreign_key` seemed to be an appropriate name.
I also named `key` `reflection_key` to match `reflection_foreign_key`.