Clean up git.objects.submodule.base imports

This reorders them lexicographically within each group, makes
spacing/formatting more consistent, and removes the old comment
about needing a dict to set .name, which had originally been on
what later became the BytesIO import but had become separate from
it. (In Python 2, there was a cStringIO type, which could provide a
speed advantage over StringIO, but its instances, not having
instance dictionaries, didn't support the dynamic creation of new
attributes. This was changed to StringIO in 00ce31a to allow .name
to be added. It was changed to BytesIO in bc8c912 to work with
bytes on both Python 2 and Python 3. The comment about needing a
dict later ended up on the preceding line in 0210e39, at which
point its meaning was unclear. Because Python 2 is no longer
supported and Python 3 has no cStringIO type, the comment is no
longer needed, and this commit removes it.)

git/objects/submodule/base.py

@@ -1,43 +1,37 @@
-# need a dict to set bloody .name field
 from io import BytesIO
 import logging
 import os
+import os.path as osp
 import stat
 import uuid
 
 import git
 from git.cmd import Git
-from git.compat import (
-    defenc,
-    is_win,
-)
-from git.config import SectionConstraint, GitConfigParser, cp
+from git.compat import defenc, is_win
+from git.config import GitConfigParser, SectionConstraint, cp
 from git.exc import (
+    BadName,
     InvalidGitRepositoryError,
     NoSuchPathError,
     RepositoryDirtyError,
-    BadName,
 )
 from git.objects.base import IndexObject, Object
 from git.objects.util import TraversableIterableObj
-
 from git.util import (
-    join_path_native,
-    to_native_path_linux,
+    IterableList,
     RemoteProgress,
+    join_path_native,
     rmtree,
+    to_native_path_linux,
     unbare_repo,
-    IterableList,
 )
 
-import os.path as osp
-
 from .util import (
+    SubmoduleConfigParser,
+    find_first_remote_branch,
     mkhead,
     sm_name,
     sm_section,
-    SubmoduleConfigParser,
-    find_first_remote_branch,
 )
 
 

test/test_docs.py

@@ -22,7 +22,7 @@ def tearDown(self):
         gc.collect()
 
     # ACTUALLY skipped by git.util.rmtree (in local onerror function), from the last call to it via
-    # git.objects.submodule.base.Submodule.remove (at "handle separate bare repository"), line 1068.
+    # git.objects.submodule.base.Submodule.remove (at "handle separate bare repository"), line 1062.
     #
     # @skipIf(HIDE_WINDOWS_KNOWN_ERRORS,
     #         "FIXME: helper.wrapper fails with: PermissionError: [WinError 5] Access is denied: "

test/test_submodule.py

@@ -458,7 +458,7 @@ def _do_base_tests(self, rwrepo):
         )
 
     # ACTUALLY skipped by git.util.rmtree (in local onerror function), called via
-    # git.objects.submodule.base.Submodule.remove at "method(mp)", line 1017.
+    # git.objects.submodule.base.Submodule.remove at "method(mp)", line 1011.
     #
     # @skipIf(HIDE_WINDOWS_KNOWN_ERRORS,
     #         "FIXME: fails with: PermissionError: [WinError 32] The process cannot access the file because"