Add a .ctags.d/ toplevel directory (#18827)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/18827
ghimport-source-id: 38f857bc29b2c2c6a71069d00c4c69ed0bef1574
Stack from [ghstack](https://github.com/ezyang/ghstack):
* **#18827 Add a .ctags.d/ toplevel directory**
Exclude build artifacts by default.
Reviewed By: ezyang
Differential Revision: D14765721
fbshipit-source-id: a785dbb2ef1df96af8e23cc65c8db2a6b67b4fce
