docs: Enable Ruff formatting of Python code blocks in Markdown

pyproject.toml

@@ -50,7 +50,7 @@ dev = [
     "pytest-timeout<3.0.0",
     "pytest-xdist<4.0.0",
     "pytest<10.0.0",
-    "ruff~=0.14.0",
+    "ruff~=0.16.0",
     "setuptools", # setuptools are used by pytest, but not explicitly required
     "ty~=0.0.0",
 ]
@@ -67,12 +67,20 @@ only-include = [
 
 [tool.ruff]
 line-length = 120
-include = ["src/**/*.py", "tests/**/*.py"]
+include = [
+    "**/*.py",
+    # Ruff formats Python code blocks embedded in Markdown files.
+    "**/*.md",
+    "**/*.mdx",
+]
+# MDX is Markdown; without this mapping Ruff would try to parse `.mdx` files as Python.
+extension = { mdx = "markdown" }
 
 [tool.ruff.lint]
 select = ["ALL"]
 ignore = [
     "COM812", # This rule may cause conflicts when used with the formatter
+    "CPY001", # Missing copyright notice at top of file
     "D100",   # Missing docstring in public module
     "D104",   # Missing docstring in public package
     "D107",   # Missing docstring in `__init__`