Fix variadic CFrame methods

[Ketasaja]

Changes

These methods are not fully documented as being variadic.

I don't know how to correctly document a variadic return when all returned values have known type, and didn't find examples, so I went with Luau's type syntax ...CFrame. Please tell me if this should instead be Variant or something else.

Checks

By submitting your pull request for review, you agree to the following:

• This contribution was created in whole or in part by me, and I have the right to submit it under the terms of this repository's open source licenses.
• I understand and agree that this contribution and a record of it are public, maintained indefinitely, and may be redistributed under the terms of this repository's open source licenses.
• To the best of my knowledge, all proposed changes are accurate.