I'd like a way to activate a rule for a subset of files; basically the inverse of per-file-ignores. In my case, I'd like to activate pydocstyle on the main module, but not tests, examples, docs, benchmarks, support files, setup.py, etc.

Current and possible options:

• Use a second ruff.toml/pyproject.toml inside the package. This is not ideal, as I don't want to add extra files (especially pyproject.toml's, as those should only be at the root of packages). This is the only one in the list that would work today (that I know of). .ruff.toml (Additional configuration file .ruff.toml #2988) would help a little, but still not my preferred solution for this case - I'd like all configuration in a single file.
• Add tool.ruff.per-file-extend-select (technically, per-file-ignores is also extend, so maybe for symmetry it could be tool.ruff.per-file-extend-select). This would then be "src/**.py" = ["D"].
• Support negation in tool.ruff.per-file-ignores like a gitignore. So "!src/**.py" = ["D"] would ignore D on anything except src/**.py files.

Thoughts?

Here's what I would have to put without this:

[tool.ruff.per-file-ignores]
"doc/**.py" = ["D"]
"tests/**.py" = ["D"]
"bench/**.py" = ["D"]
".ci/**.py" = ["D"]
"cmake_ext.py" = ["D"]
"version.py" = ["D"]
"setup.py" = ["D"]