[DOC] Update docs to show deprecate function within @ember/debug package

[elwayman02]

The current docs show it within the @ember/application/deprecations package, when it physically lives within @ember/debug.

Fixes #17185

cc: @rwjblue

[locks]

According to https://github.com/ember-cli/ember-rfc176-data, the current documentation is the correct one, so I'm closing this PR.
When we move to proper packages we should take care to handle these sort of edge cases!

[rwjblue]

@locks - The documentation is wrong for deprecate, as is ember-rfc176-data.

[rwjblue]

Specifically, importing deprecate from @ember/application/deprecations will result in the build tooling not properly stripping those deprecations.

While researching I found a number of (pretty prominent) addons using import { deprecate } from '@ember/debug (see here), but there are also quite a few more that import { deprecate } from '@ember/application/deprecations' (see here).

🤔

[locks]

Hm, should we come up with an action plan next framework meeting?

[rwjblue]

Hm, should we come up with an action plan next framework meeting?

Ya, sounds good. I think either way we need to make both imports work (and have the stripping behaviors), but seems like a great thing to discuss more broadly.

[rwjblue]

We discussed this during today's Ember core team meeting:

1. We will update the build system to ensure importing deprecate from either @ember/debug or @ember/application/deprecations have the same production stripping behaviors.
2. Update ember-rfc176-data's mapping.json to allow both locations, and mark the @ember/application/deprecations path as deprecated: true (this will aid the eslint rule's --fix to allow quick and easy conversion).
3. Update the docs (this PR) to point folks to using @ember/debug

[bekzod]

added deprecations ember-cli/ember-rfc176-data#140,
@ember/debug already striped here https://github.com/babel/ember-cli-babel/blob/master/index.js#L403-L407

[rwjblue]

@bekzod - We also need to make ember-cli-babel have the same stripping in prod behaviors for @ember/application/deprecations stuff

[bekzod]

Ok will add then

[rwjblue]

ember-cli-babel was updated in https://github.com/babel/ember-cli-babel/releases/tag/v7.8.0

[rwjblue]

All the pieces are in place now, this should be good to go now.

[rwjblue]

Thanks @elwayman02 / @xg-wang / @bekzod for pushing this forward!