Add missing decorators: @versioning_class(), @content_negotiation_class(), @metadata_class()

[qqii]

This adds the three missing decorators, fixing #9716.

• @content_negotiation_class()
• @metadata_class()
• @versioning_class()

[auvipy]

looks good

[browniebroke]

Happy to add the others with some support, as I've not used content_negotiation_class or metadata_class.

Yes, I think that if you add one, it makes sense to add all 3 that you found were missing 👍🏻

[qqii]

Sure @browniebroke, I've amended this PR to add all of them. Do the tests for content_negotiation_class and metadata_class suffice?

[browniebroke]

Looks good

[auvipy]

may be we have to update the relevant docs for these, as well?

[browniebroke]

That statement needs to be updated, the ones we're adding are accepting a single class, not a list or tuple of classes.

[qqii]

Good point. My guess is the original wording is meant to clarify that they should be used like

@api_view(["GET"])
@renderer_classes([RenderA, RenderB])
def view(request):
    pass

rather than

@api_view(["GET"])
@render_classes(RenderA, RenderB)
def view(request):
    pass

How about something like:

Each of these decorators is equivalent to setting their respective api policy attributes.
Decorators that end with classes take a single argument which must be a list or tuple of classes.

[browniebroke]

Good start, I would go one step further and explicitly outline what each form expect. Something along the lines of:

Each of these decorators is equivalent to setting their respective api policy attributes.
All decorators take a single argument. The ones that end with _class expect a single class while the ones ending in _classes expect a list or tuple of classes.