style: use Black everywhere (#2594)

* style: use Black everywhere

* style: minor touchup from review
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 13ba4e3..cf519b4 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -36,8 +36,7 @@
   - id: black
     # By default, this ignores pyi files, though black supports them
     types: [text]
-    # Not all Python files are Blacked, yet
-    files: ^(setup.py|pybind11|tests/extra|tools).*\.pyi?$
+    files: \.pyi?$
 
 # Changes tabs to spaces
 - repo: https://github.com/Lucas-C/pre-commit-hooks