Undocument public templates in object.d that are only intended for use by the compiler

[JinShil]

Now that dlang/dmd#10365 has been merged, we don't need to document those templates in object.d that are only intended for use by the compiler. Unfortunately, these may appear in the documentation for one release until dlang/dmd#10365 is folded into the release and dlang.org is updated to use the new compiler.

Also includes @ZombineDev's suggestion.

[dlang-bot]

Thanks for your pull request and interest in making D better, @JinShil! We are looking forward to reviewing it, and you should be hearing from a maintainer soon.
Please verify that your PR follows this checklist:

• My PR is fully covered with tests (you can see the coverage diff by visiting the details link of the codecov check)
• My PR is as minimal as possible (smaller, focused PRs are easier to review than big ones)
• I have provided a detailed rationale explaining my changes
• New or modified functions have Ddoc comments (with Params: and Returns:)

Please see CONTRIBUTING.md for more information.

---

If you have addressed all reviews or aren't sure how to proceed, don't hesitate to ping us with a simple comment.

Bugzilla references

Your PR doesn't reference any Bugzilla issue.

If your PR contains non-trivial changes, please reference a Bugzilla issue or create a manual changelog.

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub fetch digger
dub run digger -- build "master + druntime#2771"

[JinShil]

ping. It's an easy review and causes merge conflicts with some other work I'm trying to do.

[thewilsonator]

auto merge added.

[JinShil]

Thank you.