pyupgrade: drop redundant `open()` modes On one hand, this gets rid of some py2 cruft (like `U` and `t` modes). OTOH, I like being explict. But there's no way to disable individual transformations (and this change is part of `_fix_tokens()`, which is even harder to selectively use locally), and I'd rather have less noise when using `pyupgrade`. Warning: `contrib/synthrepo.py` appears not to have been updated to py3, as it's passing str to `error.Abort`. But since it was opening the file in unicode on py2, this change is a no-op.

--- a/tests/logexceptions.py	Mon Jan 06 01:44:46 2025 -0500
+++ b/tests/logexceptions.py	Tue Jan 07 17:28:46 2025 -0500
@@ -49,7 +49,7 @@
         frame = tb.tb_frame
 
         try:
-            with open(inspect.getsourcefile(tb), 'r') as fh:
+            with open(inspect.getsourcefile(tb)) as fh:
                 hgline = fh.readlines()[frame.f_lineno - 1].strip()
         except (IndexError, OSError):
             pass