Tweak black config (#83230)

* Remove `--safe` from pre-commit args, it's the default

* Extend exclusions instead of overriding, improve regex

.pre-commit-config.yaml

@@ -16,7 +16,6 @@ repos:
     hooks:
       - id: black
         args:
-          - --safe
           - --quiet
         files: ^((homeassistant|pylint|script|tests)/.+)?[^/]+\.py$
   - repo: https://github.com/codespell-project/codespell

pyproject.toml

@@ -74,7 +74,7 @@ include = ["homeassistant*"]
 
 [tool.black]
 target-version = ["py39", "py310"]
-exclude = 'generated'
+extend-exclude = "/generated/"
 
 [tool.isort]
 # https://github.com/PyCQA/isort/wiki/isort-Settings