Forbid extremely long line lengths in non-autogenerated stubs (#12537)

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>

pyproject.toml

@@ -3,6 +3,7 @@ line-length = 130
 target-version = ["py310"]
 skip-magic-trailing-comma = true
 # Exclude protobuf files because they have long line lengths
+# that can't be autofixed. Like docstrings and import aliases.
 # Ideally, we could configure Black to allow longer line lengths
 # for just these files, but doesn't seem possible yet.
 force-exclude = ".*_pb2.pyi"
@@ -91,13 +92,16 @@ ignore = [
     # B033 could be slightly useful but Ruff doesn't have per-file select
     "B", # flake8-bugbear
     # Rules that are out of the control of stub authors:
-    "E501", # Line too long
     "E741", # ambiguous variable name
     "F403", # `from . import *` used; unable to detect undefined names
     # Stubs can sometimes re-export entire modules.
     # Issues with using a star-imported name will be caught by type-checkers.
     "F405", # may be undefined, or defined from star imports
 ]
+# See comment on black's force-exclude config above
+"*_pb2.pyi" = [
+    "E501", # Line too long
+]
 
 [tool.ruff.lint.isort]
 split-on-trailing-comma = false