Enable the RUF029 lint in Ruff

.ruff.toml

@@ -244,7 +244,7 @@ select = [
     "RUF026",  # `default_factory` is a positional-only argument to `defaultdict`
 #    "RUF027",  # Possible f-string without an `f` prefix
     "RUF028",  # This suppression comment is invalid because {}
-#    "RUF029",  # Function `{name}` is declared `async`, but doesn't `await` or use `async` features.
+    "RUF029",  # Function `{name}` is declared `async`, but doesn't `await` or use `async` features.
     "RUF030",  # `print()` expression in `assert` statement is likely unintentional
 #    "RUF031",  # Use parentheses for tuples in subscripts.
     "RUF032",  # `Decimal()` called with float literal argument

tests/test_util/test_util_inspect.py

@@ -62,7 +62,7 @@ async def coroutinefunc():
     pass
 
 
-async def asyncgenerator():
+async def asyncgenerator():  # NoQA: RUF029
     yield