Upgrade flake8 in pre-commit and fix new warnings

Upgrading flake8 from 6.0.0 to 6.1.0 causes its pycodestyle
dependency to be upgraded from 2.10.* to 2.11.*, which is desirable
because:

- Spurious "E231 missing whitespace after ':'" warnings on 3.12 due
  to the lack of full compatibility with Python 3.12 are gone.

- New warnings appear, at least one of which, "E721 do not compare
  types, for exact checks use `is` / `is not`, for instance checks
  use `isinstance()`", does identify something we can improve.

This upgrades flake8 in pre-commit and fixes the new warnings.

Author: EliahKagan

Diff for: .pre-commit-config.yaml

@@ -1,6 +1,6 @@
 repos:
   - repo: https://github.com/PyCQA/flake8
-    rev: 6.0.0
+    rev: 6.1.0
     hooks:
       - id: flake8
         additional_dependencies:

Diff for: git/objects/submodule/base.py

@@ -1403,7 +1403,7 @@ def iter_items(
             # END handle critical error
 
             # Make sure we are looking at a submodule object
-            if type(sm) != git.objects.submodule.base.Submodule:
+            if type(sm) is not git.objects.submodule.base.Submodule:
                 continue
 
             # fill in remaining info - saves time as it doesn't have to be parsed again

Diff for: git/refs/log.py

@@ -244,7 +244,7 @@ def entry_at(cls, filepath: PathLike, index: int) -> "RefLogEntry":
             for i in range(index + 1):
                 line = fp.readline()
                 if not line:
-                    raise IndexError(f"Index file ended at line {i+1}, before given index was reached")
+                    raise IndexError(f"Index file ended at line {i + 1}, before given index was reached")
                 # END abort on eof
             # END handle runup
 

Diff for: git/util.py

@@ -1136,7 +1136,7 @@ class IterableClassWatcher(type):
 
     def __init__(cls, name: str, bases: Tuple, clsdict: Dict) -> None:
         for base in bases:
-            if type(base) == IterableClassWatcher:
+            if type(base) is IterableClassWatcher:
                 warnings.warn(
                     f"GitPython Iterable subclassed by {name}. "
                     "Iterable is deprecated due to naming clash since v3.1.18"