ruff: Enable more errors.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

pyproject.toml

@@ -99,9 +99,26 @@ django_settings_module = "zproject.settings"
 
 [tool.ruff]
 # See https://github.com/charliermarsh/ruff#rules for error code definitions.
+extend-select = [
+    "B", # bugbear
+    "C", # comprehensions
+    "M", # meta
+    "U", # upgrade
+    "W", # style warnings
+]
 ignore = [
+    "B006", # Do not use mutable data structures for argument defaults
+    "B007", # Loop control variable not used within the loop body
+    "C408", # Unnecessary `dict` call (rewrite as a literal)
     "E402", # Module level import not at top of file
     "E501", # Line too long
     "E731", # Do not assign a lambda expression, use a def
+
+    # Requires Python 3.9:
+    "U002", # `abspath(__file__)` is unnecessary in Python 3.9 and later
+    "U006", # Use `list` instead of `List` for type annotations
+
+    # Requires Python 3.10:
+    "U007", # Use `X | Y` for type annotations
 ]
 line-length = 100