Add ruff, black & isort configs

Not mandated, but for use if wanted (e.g. using "format selection" in IDEs).
Chosen defaults that best match our current style.

pyproject.toml

@@ -22,3 +22,27 @@ showcontent = true
 directory = "fix"
 name = "🔧 Fixes"
 showcontent = true
+
+
+# Not mandated to use these tools, but if you do:
+
+[tool.ruff]
+line-length = 79
+target-version = "py37"
+
+[tool.ruff.format]
+quote-style = "preserve"
+
+
+[tool.black]
+line-length = 79
+target-version = ['py37']
+skip-string-normalization = true
+
+
+[tool.isort]
+profile = "black"
+line_length = 79
+force_grid_wrap = 4
+lines_after_imports = 2
+combine_as_imports = true