include linter explanation

.flake8

@@ -1,4 +1,5 @@
-# flake8 does not support pyproject.toml (https://github.com/PyCQA/flake8/issues/234)
+# this file only exists for legacy compatibility with editors that expect it
+# you should use `ruff` for linting and formatting, and not `flake8`
 
 [flake8]
 max-line-length = 79